My outline for Mat 1:
Mat 1:1-17 genealogy of Jesus Christ
Mat 1:18-25 chiastic structure
1a) Mat 1:18a, The birth of Jesus Christ was as follows;
1b) Mat 1:18b, Betrothal + purity of Mary and Joseph, she conceived by the Holy Spirit;
1c) Mat 1:19, Joseph considered putting her away secretly;
1d) Mat 1:20, Angel appeared, saying, Do not be afraid to take Mary your wife;
1e) Mat 1:21, She will bring forth a Son, Jesus, He will save His people from their sins;
central axis) Mat 1:22, “So all this was done that it might be fulfilled which was spoken by the Lord through the prophet;”
2e) Mat 1:23, The virgin shall bear a Son, Immanuel, God with us;
2d) Mat 1:24a, Joseph did as the angel commanded;
2c) Mat 1:24b, And took to him Mary his wife;
2b) Mat 1:25a, He did not know her until she brought forth her firstborn Son;
2a) Mat 1:25b, He called His name Jesus.
The central axis emphasizes that the birth of Jesus was the fulfillment of prophecy. He is the Promised Seed of Gen 3:15, of whom it was prophesied that He would be born of woman and crush the head of the serpent. The serpent, whose head He will crush, brought about the separation of God and man. Jesus will undo that and bring about their dwelling together again, the matching pairs show us, by saving His people from their sins.
That He was born of a virgin also fulfills multiple covert prophecies of the Promised Seed throughout the Hebrew Scriptures: the patriarchs and forefathers, and types of Messiah in Scripture, all had mothers for whom it was likewise impossible to conceive. Just as it should be impossible for Mary to conceive, being a virgin, it should have been impossible for Sarah to conceive, being barren and furthermore, beyond menopause. It was impossible for Rebekah and Rachel to conceive, being barren. (Rachel was the mother of Joseph, the type of Messiah among Jacob’s twelve sons, whose life illustrated the ministry of Messiah Yeshua in His first and second comings).
The mothers included in Jesus’ genealogy likewise experienced impossible births, as their relationships were forbidden by Torah: Tamar bore Judah’s sons, even though she was his daughter- in- law. Rahab bore Salmon’s sons, even though she had been a Canaanite and a harlot. Ruth bore Boaz’s sons, even though she had been a Moabitess. Bathsheba bore David’s sons, even though she had been the wife of another. The Torah and Hebrew Scriptures in this way prophesy that the birth of the Promised Seed will be miraculous.