Now the birth of Jesus Christ was as follows: when His mother Mary had been betrothed to Joseph, before they came together she was found to be with child by the Holy Spirit.Matthew has already explored Jesus' lineage (see Matthew 1:1-17), but he is now about to describe the birth of Jesus Christ in greater detail. Now the birth of Jesus Christ was as follows... What Matthew is about to state is indisputable; it is exactly what happened and absolutely true, just as the rest of Scripture.
Jesus, who is God, became flesh. He became man. He was born by an earthly mother, but had no biological father. Mary, Jesus' mother, was betrothed to Joseph. Alfred Edersheim writes in The Life and Times of Jesus the Messiah:
From that moment Mary was the betrothed wife of Joseph; their relationship as sacred, as if they had been already been wedded. Any breach of it would be treated as adultery; nor could the band be dissolved except, as after marriage, by regular divorce. Ten months might intervene between the betrothal and marriage.Barring any sort of major tragedy, Mary and Joseph's marriage would certainly come to pass. But an apparent tragedy did occur, before they came together she was found to be with child. When Joseph first heard this, he must have been shocked, "Mary... pregnant... what? Mary would never— there must be some strange explanation for this...".
There was. Mary was found to be with child by the Holy Spirit. Jesus' conception was not the result of immorality; rather, Jesus has always existed and always will exist. His entrance into the world was by divine means. Mary likely told Joseph all of these things and of her encounter with the angel Gabriel (Luke 1:26-33)— now it came down to one thing, would Joseph believe her?
Joseph's Dilemma - Matthew 1:19
Mary's Embarrassing Privilege - Matthew 1:18
Jesus' Purpose: To Save His People From Their Sins (Part 1) - Matthew 1:21
Isaiah's Prophecy: It's Fulfillment (Part 1) - Matthew 1:22-23
The Lineage of the Messiah - Matthew 1:1-17