In our study of Matthew chapter one, we see the family tree of Jesus and the fact that He was legally Jewish. This gospel account is written for the Jewish population and it lays the important foundation to show the fulfillment of Messianic prophecy.
"This is the genealogy of Jesus the Messiah the son of David, the son of Abraham:" NIV translation
This gospel account begins like a legal document. We see that its purpose is to show the direct relationship between Jesus, David, and Abraham.
God promised David that his throne would be established forever (2 Samuel 7) and so it was important that Jesus was his descendent. This is known as the Davidic Covenant.
God promised Abraham that he would be a great nation and that all people on the earth would be blessed through him (see Genesis 12). This is known as the Abrahamic Covenant and Abraham is known as the father of the faith.
"Abraham was the father of Isaac, Isaac the father of Jacob, Jacob the father of Judah and his brothers, Judah the father of Perez and Zerah, whose mother was Tamar, " NIV translation
We notice that it is from the line of Jacob that Jesus came and not Isaac's firstborn son Esau (Jacob's twin brother). We are reminded that it was God that selected Jacob and that He told Rebekah that the older would serve the younger (Genesis 25). God promised Jacob (whose name He changed to Israel) the land and that kings would be among his descendants (Genesis 35). This passage shows that Jesus was from the tribe of Judah which was important to fulfill the prophecy of Jacob (Genesis 49). There he said that the tribe of Judah would produce the leaders until the final kingdom is established on the earth.
We are also introduced to the first of four Gentile (non-Jewish) women in Jesus' family tree. Tamar, a Canaanite woman, was actually the wife of Judah's son Er until the Lord put him to death. After that, she tricked Judah into sleeping with her so that she could become his wife (Genesis 38). It is interesting to note that Judah said of her that she was "more righteous" than he was in this event.