If Joseph is not the father of Jesus then what is the purpose of Jesus' genealogy as mentioned in Matthew and Luke?

Answer 1

Joseph was Jesus' stepfather. As such, his genealogy was important to Jesus. While Jesus was the seed of David through His mother Mary, His inheritance of the throne of Israel came through Joseph, as all royal inheritances were passed through the fathers. As the adopted son of Joseph, Jesus was the full heir of David. Matthew was concerned with Jewish law, and thus emphasized Jesus' inheritance from David through His adopted father Joseph. Luke traced Jesus physical genealogy through Mary. Incidentally, Luke later refers to Joseph as the son of Heli, who was actually shown in the Jerusalem Talmud to be Mary's father. This was not a mistake. The Jews often refered to sons-in-law as sons. There is scriptural precedent in other Jewish genealogies. God was the Father of Jesus, through the Virgin Mary's conception by the Holy Spirit. The Genealogy showed the generations that passed down, in which the lineage of Christ would pass. It was foretold in Scripture in Isaiah and other prophecies, that a child would be born in Bethlehem, and he would also pass down through the line of David, which Jesus is in his genealogical lineage.

=== ===

Answer 2

There are many differences between the two genealogies, such that neither genealogy could be historically true. However, The Bible can not contain errors, so some have suggested that Matthew's account provides the genealogy of Joseph, while Luke's account provides the genealogy Mary - in spite of Luke 3:23, which clearly identifies this account as also being the genealogy of Joseph. Raymond E. Brown (An Introduction to the New Testament) says "Inspiration does not guarantee historicity or reconcilability; otherwise God should have inspired the two evangelists to give us the same record." Where the two genealogies must agree in order to be historically meaningful is in the paternal grandfather of the great Zorobabel, who is included in both genealogies. Matthew and Luke both say that Zorobabel' father was Salathiel, but Matthew says that Salathiel's father was called Jechonias, while Luke says his name was Neri.

Having recognised that the two genealogies were fictional, we should look for literary purposes for their inclusion in the respective gospels. Of course, both authors wanted to 'prove' that Jesus was descended from David, and also from Zorobabel. Both used numerology to prove that Jesus was destined for greatness. By ignoring three kings in the Old Testament, Matthewdemonstrated that there were 14 generations: from Abraham to David; from David to Josiah; from Josiah to Jesus. By inserting ancestors not recorded in the Old Testament, Luke had great men occur in multiples of 7 generations starting from Adam, including Enoch at 7, Abraham at 21, David at 35, Jesus at 77.

Another reason for the author of Matthew was to draw parallels between Jesus and Moses, so he gave the name Jacob to the father of Joseph, just as in the Old Testament. Whereas Matthew has Jesus descended from the royal line, the author of Luke followed a line of commoners all the way from Zorobabel to David, in line with his focus on the poor.