Engagement in OT Israel was legally binding. The punishment for having an affair was death.

Matthew focuses his birth narrative on Joseph instead of on Mary like Luke does. The stories are radically different. The only real overlap is that the angel says, “Do not be afraid.”

Without an angel intervening every single one of us would have responded the same way that Joseph did to Mary’s outlandish story. Saying Joseph was a just man means that he follows the law closely. He had to divorce her if Mary was adulterous. Joseph could have made things public and Mary would have been put to death or at least extremely shamed. It was retaliation to make the divorce public in this honor/shame culture.

Matthew is showing that God often works in the most unexpected ways. He shows that the lineage of Jesus and his virgin birth is so hard to believe that even Joseph doesn’t believe.

Why the virgin birth and is it necessary?

We affirm the truthfulness of scripture. Isaiah 7, Matthew and Luke emphasize the virginity of Mary. Selecting some portions of scripture and discarding others puts us over scripture verse scripture over us.

It has always been believed by the church. We shouldn’t cling to or reject beliefs simply because they are old. Reviewing who has upheld beliefs lends credit to them. This is one of the five things that has been considered an essential to faith is arrogant.

Because of original sin. (Maybe) Some would say because Adam wasn’t just deceived, but chose sin, we are born with a sinful nature. Eph 2:3 If original sin is guilt and is passed through the father’s genetics, Jesus had to have no father. But Romans 5 attaches the idea of guilt from sin not to genetics, but to choosing to sin. Are we sinners because we sin or do we sin because we are sinners. Torah law says that a son cannot be punished for the sin of his father. At the same time we are born with the desire to sin. We don’t need temptation to sin.

Because of the hypostatic union. In the unified one person of Jesus there are two natures: human and God. Without the virgin birth Jesus cannot be anything more than a prophet. Because he was born of a human and God he has both natures. If he had a mother and father he would have only human nature. If he just appeared and was not born he would only have the nature of God.

Without the virgin birth we don’t have Emmanuel; we don’t have a savior dying for us. We need this to trust that we have been forgiven and made right with God.