What was Joseph's reaction to the news of Mary's pregnancy?

The answer will depend on whether you follow later “Church Fathers” and medieval myth or read the Bible as a historic document in its original Hebrew and Greek for the Jewish audience it was originally intended for. The Gentile Church after the destruction of Jerusalem in 70 CE interpreted the NT in a way to conform to Hellenistic and semi-pagan culture. This took for granted that demi-gods were the product of gods like Zeus descending on 15 year old virgins and producing demi-gods. 

Dionysus, alleged son of Zeus and Persephone

https://en.wikipedia.org/wiki/List_of_demigods

Jerome was obsessed with virginity and the Virgins of Rome. (Rome would disappear if there were no more Vestal Virgins.) He said both Joseph and Mary were perpetual virgins. He made matters worse with mistranslations from Greek to Latin in his Vulgate NT.

How would a Jew, a believer in Jesus Christ, read the Greek NT?
1. He would understand Hebrew marriage was different from Roman marriage or modern marriage. Genealogy dominated all society among the 12 tribes. That is why the NT starts with Christ’s pedigree and the Hebrew scriptures in their order ends with Chronicles. The Messiah had to be a lineal descendent of David, John 7:42 and as Paul says Romans 1:3.

2. Parents therefore arranged marriages of their young children. When they reached their teens and first maturity the girl and boy could agree and they were ‘betrothed’ by a ceremony of qiddushin or erusin. This meant they were married in the sense that only a divorce ( a ‘get’) could break the bond. (Far different from present day ‘engagement’). The girl still lived at her father’s house until the bridegroom had built a home for her and was ready to assume all duties of its head of household. Then he called for her and the community to celebrate the wedding in a ceremony called nisu’in, the ‘home-coming’ or ‘coming together’ mentioned several times in the NT in Matt 25, Revelation etc.

3. When the NT says Joseph and Mary (Mariam in the Greek) were betrothed it means they were married according to the Hebrew custom. Once the girl/ woman left her father’s home the couple could enjoy their marriage and man became fully her husband. The nisu’in was an extra ceremony. For Joseph it was not normally possible to bring Mariam to Bethlehem, because as the hereditary home of King David it had been destroyed by Herod, who saw all Davidic descendants as enemies to his claim as king under the Romans. The NT says there was ‘no place’ there. Only shepherds were allowed there. Then Herod used the Roman registration decree to get Davidic claimants to register in Bethlehem. It was highly dangerous for Joseph. More so for Mariam who was both old and pregnant, Luke 1:36. God, through an angel, told Joseph ‘not to be afraid to take your wife with you,’ Mt 1:20, because the child was conceived according to God’s plan.

4. Matt ch 1:18 says: (a) they were betrothed, that is married in our sense. (b) Before their ‘coming together’ Mariam was found to be pregnant by God’s grace of his spiritual action. The term ‘coming together’ refers to nisu’in the celebration of the community at the bridegroom’s home. It is used both in Hebrew and Greek secular literature to mean the ceremony of a bridegroom taking his new wife to his home and the community coming together to celebrate it. The next verse has nothing to do with divorce. The Greek word means putting aside, that is putting her in a safe place and avoiding a long journey during pregnancy and possible death by Herod’s men.

5. To create the virgin conception myth, v 25 was distorted or misunderstood by the early Gentile church. It was ripped out of the chronological sequence. They ignored the Jewish and Christian culture.

And he did not know her till she had brought forth her firstborn son.

Read the context. Mariam was already pregnant. Jewish purity law forbade intercourse with a pregnant woman. If this occurred the legalists could say the child was not pure. This was especially important for Joseph and Mariam and any claim to priesthood and royalty of their offspring. Early Christian/Nazarene writings take the same view about forbidding intercourse once the wife is pregnant.

6. Joseph and Mariam would clearly be both shocked and delighted that they were to have a child as they were both in their old age, Luke 1:36, and it was a miracle as was the child Isaac of Abraham and Sarah and many other faithful couple in the Bible. Children in old age is a sign of God’s hand. In Jewish law a woman is considered a virgin before she menstruates. An old woman who is past her menopause is also considered to be a virgin for the purposes of her fulfilling the laws of purity called Niddah described in Leviticus 12 (=Luke 2:22) and Lev 15:19ff.

7. The semi-pagan Roman-instituted church of Constantine wanted nothing to do with the Jews. Medieval followers of Jerome etc confused the NT history with that of Hellenistic deities and hang-ups about virgins because the Greek and especially Hebrew scriptures were forbidden. The Latin Vulgate was gibberish to many priests and their parishioners. Hebrew scrolls were burnt. Translations into local languages were forbidden on pain of death. Ignorance reigned.

8. The Bible is quite clear about the two spheres of begettal. One is that of humans in marriage. Christ explained that a spiritual, second begettal was possible through the Spirit of God, John 3, to Nicodemus. The confusion caused by the pagans who claimed to be Christians has hidden this greatest truth from present-day, would-be followers of the Eternal God. The authentic documents are recorded more fully at "Jesus, James, Joseph and the past and future Temple" N54final version and in the paper version.

Conjunctions, the Bethlehem Star Prophecy and Precision Astrophysics

Humankind needs to learn humility when gazing at the stars and planets. It is clear that mankind was not their maker. What man can make is insignificant, even in relation to our own home.

But I disagree with those that say the Stars and Planets do not have significance. They speak for the Great Creator and Information Giver who first designed and then made them all.

The Earth is full of intricate living organisms from bacteria to massive creatures like whales and elephants. Finely balanced physical planetary characteristics are necessary to maintain them. Earth was made for humankind. The environment is finely shaped to sustain him and also provide teachings of the Creator who made all things.

But when it comes to wider universe, many of the humans who benefit from the wisdom and construction of the planet fail to see the same hand in the stars and galaxies. That is a big mistake. The Creator who finely tuned all the constants of the laws of physics and life, did not throw the stars out at random. 

Here are some reasons to believe otherwise.

Stars as Witness

There are many references to stars and the heavens in the Bible. From its first words of Genesis, the Bible confronted to nonsense of the pagans in their errors, errors that were maintained into the twentieth century. 

In the Beginning God created the heavens and the earth implies that at a certain moment the entire universe was created. The pagans like Aristotle believed that the universe had always existed. Scientists up to the middle of the 1900s also thought this. Why? Because the dominant materialist philosophy wanted to deny a creation because logically a creation must involve a Creator. That was well known even in ancient Greek logics and philosophy.

Scientific advance showed that this fallacy of an eternal universe could not be maintained. The stars were moving away from us. And logically, at one time they must have all come together at the beginning. The sceptical materialists tried to downplay this fact that bust their materialism apart by calling it the Big Bang.

The Bible shows these materialist/ atheists have much more to learn. 

Take the movement of the stars mentioned in the book of Job as some examples. Learn some lessons from the Creation.   

Pleiades

Let us go to one of the signs of the Hebrew zodiac: the Pleiades, Hebrew Kimah. 

The Eternal God asked Job out of a whirlwind, Job 38:31:

Can you fasten the harness of Pleiades? (New Jerusalem)

Can you bind fast the cluster Pleiades? (Bullinger) 

Can you bind the sweet influences of Pleiades? (KJV)

The Pleiades are known as the Seven Sisters. What does it mean fastening or binding them? Only recently the most powerful telescopes make it clear. Imperceptibly to the naked eye they are moving closer together. This data was collected from massive earth telescopes in Australia and elsewhere and combined with recent data from the Gaia space satellite launched in 2013.

Careful measurements with the Gaia space telescope and others show the stars of the Pleiades are slowly moving in the sky. One star, Pleione, is now so close to the star Atlas they look like a single star to the naked eye.

But if we take what we know about the movement of the stars and rewind 100,000 years, Pleione was further from Atlas and would have been easily visible to the naked eye.

The writer of the book of Job had magnificent eyes or maybe, as the book says, someone listened to the Great Information Giver who made the stars.

Orion

What about the other part of the verse about Orion, Hebrew Kesil:

Can you loosen great Orion's bands?

The three stars of Orion's belt are a line-of-sight constellation. Two stars may now be shown to look like they are approaching each other while the third is drifting out of the arrangement and may eventually break up the three-star line-up completely.

Arcturus

Next verse:

Can you guide Arcturus and his sons?

Highly unusually Arcturus, Hebrew Aysh, has a stream of 52 stars connected to it. That was discovered in 1971. Equally unusually Arcturus, one of the greatest stars in the universe, is a runaway. It has a speed of 257 miles a second. That compares with the normal under 25 miles per second and our own sun's 12 1/2 miles a second.

Arcturus and his sons are all on their own course at rip-neck speed.

Can the movement of Planets, Stars and Constellations predict the future? Can they show events of the past?

Humans have no ability to move stars. Their course can be worked out by the eternal laws of mathematics and physics. We have a sure means to see how their position predicted events before, when and after such notable events happened. Humans have no excuse for not paying attention.

 Eternal God, creator of the Universe

Humans are subject to error and tempted by deliberate deceit. Humans cannot muck with movement of the planets, comets and stars. That was the reason that Kepler, Newton, Whiston and other believing scientists tried to determine what, when and where was the Star of Bethlehem.
The heavens have an extraordinary, clear and unambiguous message. But what is it? We should not seek it in pagan, Chaldean astrology.
What does the Bible say? What is the configuration of the heavens in the autumn of 3/2 BCE?
Astronomers in the past could work this out. Many people in the early centuries were far more skilled and literate in astronomy and its real significance than people today -- in spite of so-called popular astrologers.
They looked at the sky at night and knew the stars and the movements.
But how do you see what was happening way back in the past?
You can also this ancient stellar display in the heavens at a planetarium when they set the mechanism back 2000 years.
Now with the help of the computer and software it is possible for anyone at home to see exactly the movement of the planets back into the distant past.
What did the night sky look like in 3/2 BCE?
It is an extraordinary fact, as Dr Ernest L Martin points out, that

• on only one day in 3 BCE was the moon under the feet of the constellation of Virgo, the virgin and the sun 'clothed' her. 
• It was when it was the first crescent of the New Moon. 
• It occurred on 11 September. 
• It remained there for only a few hours. 

Click the link here to have a description of the Ancient Astronomy of this time by Dr Michael Heiser.

One reason people observed the stars was that it was religiously significant because observation of the New Moon was essential to define months and proclaim the New Year. What is even more extraordinary is that 11 September was the beginning of the Feast of Trumpets in the Hebrew calendar. Revelation 12:
'And there appeared a great wonder in the heaven; a woman clothed with the sun and the moon under her feet, and upon her head a crown of twelve stars.'
This year is also confirmed by Luke's statement that Jesus was 'about thirty years old' when he began his work as chief priest and teacher in the Temple. This has to be understood in relation to the Hebrew inclusive arithmetic system and the Jewish secular new year (common through the eastern Roman Empire). It is also defined by the known dates for the reconstruction of the Temple by Simon Boethus under Herod the Great.

The date of the birth of Jesus is 1st Tishrei in year 3 BCE in the autumn.
This fits all the criteria of

• historical events in the NT and Josephus
• Hebrew chronology
• Hebrew festivals
• Hebrew interpretation of the movement of the planets in 3 BCE,
• The near unanimous report of nearly all early writers of the first centuries.

The heavens don't lie.

Tom Paine debunks the Virgin Birth. What else did he miss?

Is the belief in Mary's Virgin birth is necessary for salvation? The answer to the question is "It depends on what you mean by Virgin Birth".  The conundrum arises because people today seldom read the Bible logically. They confuse what the NT actually says with common custom of "Christmas", nativity and Virgin Birth (that is virginal conception). There are animals and stables, mangers and the story of 'no room for them in the Inn'.
This mythology derives from the non-Jewish and often paganized church of the third and fourth centuries. The dogma of the BVM (Blessed Virgin Mary) is maintained up to the present by Roman Catholics, Protestants and others.
The 18th century best-selling writer and revolutionary,Thomas Paine, opposed this false interpretation. Fine! but he was fighting many shadows and falsehoods. The paganized accretions of the church also added quite a number of falsities that are still present today.
Mary's name was not Mary -- it is Mariam in the Greek NT. This is equivalent to the name of the sister of Moses, a Levite. She was not a young girl but was an old woman like her cousin, Elizabeth. And Elizabeth was equivalent to the Jewish name, Elisheva, Aaron's wife.
Mariam was married and still a virgin according to Hebrew definitions. There is no stable in the NT. There is no inn. There is no cave. The city of David, Bethlehem, was not full of people. It was probably empty except for a few shepherds. (Claiming descent from David was a death sentence in usurper 'King' Herod's regime. No one was even called David in NT times!) No animals, and no stable. But Mariam did not give birth alone. That would have invalidated the genealogy. She needed at least two or three proven honest witnesses.
These false accretions came from Mithraism that was absorbed into Roman religion around the first century. The RC Virgin Birth came from classical pantheism were the gods descended and took human virgins to procreate the demigods.
The Magi did not come at the birth but a year or two later. And there were not three, there were probably hundreds or thousands of Parthian Magi in a caravan that caused the whole of Jerusalem to tremble with fear of another Roman-Parthian war. Parthia had defeated Rome in numerous times in bloody wars and a peace treaty had been made less than 20 years earlier.
And as Paine rightly points out this BVM business adds impossibility to improbability and the illegitimacy of the RC story. In fact it demolishes it. It requires patience and logic to discover and expose lies and falsehoods. A contemporary of Paine was the famous scientist Joseph Priestley. Like many of the scientists of his day, he wrote a huge amount of theology, as in the age of Reason, the logical methodology required was the same. Paine was not up to par on reason. I recommend Priestley's books such as "History of the Corruptions of Christianity" 1782, 'History of early Opinions concerning Jesus Christ'', 'Discourses on Evidences of Revealed Religion' (delivered at the church of the Universalists, Philadelphia 1796 and dedicated to John Adams).
What is important is less the details of history but a willingness to find the truth, for example about the Resurrection and the NT as a whole and act on it.

Tom Paine is considered a hero of American Independence. Born in England, he became an American citizen and then in France during the Revolution was elected to the French Assembly! He wrote a number of books like Common Sense, The Rights of Man, and the Age of Reason, that were best sellers of his time. They still sell well today.
He was raised on the Bible and was able to expose quite a bit of the hypocrisy of the religion of his day. He described himself as a Deist and his rejection of traditional beliefs alienated him from many of his contemporaries.
He was also in conversation with scholars after he wrote this book, so we don't know his final thoughts. He was right to ask questions. But not all of his conclusions are correct. What is useful is the effort to separate the original truth about Christ and the later traditions of men and politicians.
If you consider the so-called Christian traditions of the RC-Protestants as a series of falsehoods overlaid on the biblical account, Paine exposed and removed some of the most pertinent. He said about the Virgin Birth in the Age of Reason that:

Were any girl that is now with child to say, and even if to swear it, that she was gotten with child by a ghost, and an angel told her so, would she be believed?  Certainly she would not.  Why, then, are we to believe the same thing of another girl, whom we never saw, told by nobody knows who, nor when, nor where?  How strange and inconsistent it is, that the same circumstance that would weaken the belief even of a probable story, should be given as a motive for believing this one, that has upon the face of it every token of absolute impossibility and imposture!"

No one would believe her then. No one should believe her today. Yet millions are taught this unbelievable and unprovable claim by a teenager as the foundation for religious belief and obedience to a denomination. Some blasphemously call this girl 'the mother of god.' That is a pagan title of the pagan Queen of Heaven.
Where did the Virgin Birth come from? Why is it held so firmly? The overlay here is ancient and pagan. It is that of the long-held, Greco-Roman gods impregnating human virgins. 
How did paganism get mixed up with Christianity? Thank the fourth century imperial church of Emperor Constantine for this mish-mash! Paine is right to show that such assertions don't make sense. They render the improbable impossible. He exposes it as an imposture. He was a free man and spoke his mind. In the Middle Ages the imperial church would have required his life. In fact Paine almost lost his life for his frankness.
The fraudulent doctrine comes by combining (syncretizing) current beliefs to make a new imperial religion acceptable to all. The imperial church and the popes gave 'Christian' names to the pagan gods. But this allegation of an unmarried teenager claiming a Virgin conception by a pagan-style god is at odds with the Bible.
The NT says the opposite. Jesus had a human father. Mariam says to Jesus about Joseph: 'Your father and I have been searching for you.' The disciples say that Jesus is the son of Joseph. Did the popes know better than the real mother and father?
But wasn't Jesus also divine? Where Paine does not analyze it is in the matter of a second birth mentioned to Nikodemus in John 3. This begettal occurred at the baptism of Jesus as an adult human. It was physically seen as 'the form of a dove'.
A further overlay of lies or ignorance that Paine does not speak of is the confusion of Mariam's marital state. Non-Jews of the RCC etc applied the Roman or  even modern concept of what 'betrothal ' is to the NT. Among Hebrews it was different. It is not Engagement. In Hebrew and biblical custom betrothal=Qiddushin= consecration. It means marriage vows and a divorce is needed to break it. So Mariam was married and with child.
It was clearly a miracle to everyone because she was an old woman! She was pregnant at what was definitely a post-menopausal age. 'By (the) holy spirit' means by the grace of God as elsewhere in NT.
Luke 1:36 says both Mariam and her cousin conceived in their old age (gera as in geriatrics) and as Sarah, Rebekah, Hannah and other holy women. Isaiah 7:7 speaks of 65 years but it is not clear whether this also refers to a married virgin.
No text speaks of a 14-year old. The 14-year old 'Mary' comes again from paganized demigod theology. The Romans assumed anyone older than 14 would not be a virgin.
There is a further overlay of ignorance or lies relating to what modern churches take a 'virgin' to be and what virgin meant to the Jews and in the Bible etc. The first century Jewish Christians were called Nazarenes Acts 24:5 and continued into later centuries. They were clear on these matters. Gentiles were confused.  Paine did not explore the sources of these errors although some of the scientist-theologians like Newton, Whiston, Priestley, Boyle did.
The scientific method requires that each step is proven before one moves to deducing a conclusion. That's why Paine needs to be read, checking and verifying with the Bible, other authors and Jewish writings. Some of this is summarized in chapter 15 of the free eBook
https://www.academia.edu/25051668/Jesus_James_Joseph_and_the_past_and_future_Temple_Version_N36