The focus of Matthew's genealogy is clear. The significance of Jesus is deeply rooted in the history of the Old Testament, so deeply that the blessings promised to Old Testament Israel find their fulfillment only through Him.
Can the answer to the question, "Who is Israel?" be established by merely a genealogical record, even if it is a royal genealogy? (Here the author mentions Matthew 3:9.)
God's promises are for Israel, but Israel is not established simply by birthright. The blessings are not automatically guaranteed by preserving the purity of an Israelite or Jewish gene pool or an impeccable family tree. Much more is involved --and this is hinted at in Matthew's genealogy of Jesus.
This hint comes with the women listed in Jesus' family tree.
They are not the four famous matriarch's of Judaism--Sarah, Rebekah, Rachel and Leah--but four women who are foreigners and not especially "holy": Tamar and Rahab the Canaanites, Ruth the Moabite, and Bathsheba, the wife of a Hittite. At the very least, Matthew is saying that the true descendants of Abraham are not preserved by their purity of descent. As the people of God, Israel was always intended to be and to become a universal people, not limited by racial purity. These four women testify to God's initiative in incorporating outsiders into Israel and to His astonishing strange providence in placing these women into the royal lineage in which lay the hope of Israel. Thus even in this genealogical record the emphasis falls not on human initiative and planning but on God's intervention as it overcomes human obstacles and historical dilemmas on behalf of the Messiah who was to come. God decides who belongs to Israel.
God's election shapes the genealogy of true Israel, and that election becomes especially apparent in the fifth woman mentioned, "Mary, of whom Jesus was born, who is called the Messiah" (Matthew 1:16). The genealogy notes a "holy irregularity" in describing Jesus' ancestry. Joseph is simply "the husband of Mary", not the begetter of Jesus. Jesus was born of Mary.
Therefore, though He is linked to the history of His people and is comprehensible only within the interconnectedness of that history, yet He is beyond history, beyond its potentialities and possibilities. He is more than His ancestry could produce. He represents the intervention of God, the creative work of the Holy Spirit, which was active once in creation and promised again the messianic salvation of the end time. God provided what human history could not.
Israel came into being in the mysterious election of God and depends for its continuing existence on God's gracious and miraculous actions. Therefore the definition of Israel can never merely be a matter of proper genealogical connections, even if God chooses to use such connections. Matthew's genealogy of Jesus demonstrates that in the end, and often along the way, the genealogical connections to Abraham were insufficient and that God had to intervene to preserve a people for Himself. Jesus Christ is that intervention on our behalf. In His person and in His work, Jesus is all that Israel was meant to be because in Jesus, God Himself takes the place of His covenant partner in order to secure the continuity of His covenant with Israel. Jesus is Emmanuel, God-with-us. Consequently, the definition of true Israel is forever shaped by this action. Israel can never again be defined apart from Jesus Christ.
Matthew's genealogy of Jesus signals that a new beginning as been inaugurated, a new era in Israel's history and a new area in the history of the world, for in Jesus God's centuries-old promises to Abraham and David have entered upon their historical fulfillment. After centuries of oppression and disappointment, of disobedience and failure in mission, Israel is renewed and the nations will be blessed. Through His providential guidance and miraculous grace, God has answered the question, "Who is Israel?"Jesus & Israel: One Covenant or Two? by David E. Holwerda, p. 34-36, selected portions.