The different versions of the geneology of Jesus in Matthew 1:1-17 and Luke 3:23-38 are probably the most overlooked parts of the narratives of these two gospels. They do not appear in the three year lectionary of Scripture readings for Sundays and holy days. Preachers who do not follow the lectionary rarely, if ever, use them as texts for their sermons. Either of them could be read on a Sunday in Advent or, better still, the Sunday after Christmas Day. The congregation might find a sermon preached on Jesus' geneology intriguing if for no other reason than their doubt that it could be done.
Any preacher who chooses to preach on one of these different geneologies faces some challenges. One challenge is to address all of the complicated questions posed by biblical scholarship. Another is to decide how to proclaim the Gospel of Jesus Christ from one of these texts. As usual, the decision about how to proclaim the Gospel from the text would be governed by the theological purpose of the evangelist who included it in his gospel.
Consider some of the issues that emerge in understanding these texts. For one thing, the two geneologies do not match. Matthew begins with Abraham and works his way down to Joseph, the husband of Mary. Luke begins with Jesus and works his way back to Adam. Many of the names in both lists of the generations do not match. There is no way to completely harmonize the two different geneologies. Raymond E. Brown speculates that Matthew used a couple of geneologies of the Davidic lineage that were already available to the public and made some changes, such as the inclusion of women's names, while Luke's geneology for the generations after the exile may have been based upon Joseph's "family list" (The Birth of the Messiah, Image Books, 1979, Pp. 57-94). However the differences ought not distract from an obvious point, which is that Jesus' geneology is a geneology of his ancestors, not his descendants because, as Brown says (p. 67), "history has reached its goal in Jesus." As Mark 3:31-35 indicates, from now on whoever is a disciple of Jesus is a member of his family.
Moreover, there is the oddity that the only evangelists to provide a geneology for Jesus are the same ones who tell the story of the virginal conception of Jesus by Mary! Since the two evangelists considered the virginal conception to be a theological event (the special creation of Jesus' human nature by the Holy Spirit) rather than merely a theological idea (the metaphorical expression that Jesus' natural conception was the will of the Holy Spirit), we infer that they considered Joseph to be the legal, if not biological, father of Jesus. Attempts to demonstrate that Luke's geneology is really that of Mary rather than Joseph are not persuasive despite some ingenious theories [such as the theory that Joseph, who is son of Jacob in Matthew, married Mary, who is alleged to be the daughter of Eli ( listed as the father of Joseph in Luke) so that Joseph becomes Eli's heir as well as Mary]. In Jesus' time and society, legal paternity mattered as much as biological paternity in a culture shaped by the ancient Israelite tradition of levirate marriage in Deuteronomy 25:5-10. At any rate, it would have been inconceivable in the primitive Jewish Christian community not to have a geneology for Jesus because, in the Hebrew Scriptures, the relationship between generations is considered to be as much a part of God's design for the crreation as the relationship of man and woman. Like everyone else, Jesus's story fits into the story of the succession of the generations.
Another way to account for the two evangelists' inclusion of a geneology along with a story of virginal conception is that both evangelists in their own way were attempting to honor two traditions they received--the tradition of Jesus' descent from King David and the tradition (in two independent forms) of the virginal conception. Relatives of Jesus were known to be of Davidic descent. The grandsons of Jude, the "brother" of James and Jesus (Jude 1:1), were brought before Emperor Domitian around A.D. 90 on the suspicion that they were politically dangerous because they were descendants of King David. It is likely that Joseph was a descendant of David in one of the non-aristocratic lines; indeed, in Luke's "family list," Joseph is a descendant of David's son Nathan rather than of King Solomon. By including a geneology of Jesus that supported the firm tradition that Jesus was in the (legal) line of David alongside the tradition that he was conceived by the virgin Mary, the two evangelists in their own ways could honor both traditions they had received without any real conflict in their minds.
We must also keep in mind that in the early church Jesus' Messiahship, and thus his status as "David's son," is based primarily on his resurrection from the dead by the God of Israel (Acts 2:36). In Luke 20:41-44, Jesus himself does not repudiate the Davidic descent of the Messiah, but he does emphasize that what makes one a Messiah is God's choice, not the Messiah's descent from David. In Romans 1:3-4, Paul (who gives no evidence of knowledge of the tradition of virginal conception) assumes that Jesus was "descended from David according to the flesh," but was "declared to be Son of God with power...by resurrection from the dead...."
When we consider the general problems posed by the two different geneologies of Matthew and Luke, we may conclude that they should not be taken literalistically. There may be some genuine historical information in them, especially if Luke is using a "family list" as Raymond E. Brown suggested. There also may be some connections between the two geneologies we shall never know because of the compexities in geneology generally, such as the conundrums of the same persons known by different names, different persons having the same name, possible levirate marriages, and so on. Anyone who studies their own geneology understands these complexities. (There is a note in the papers of 19th century historian Lyman Draper discussing his confusion over the many persons with the same name of "Abraham Whitaker" in my own family.) Matthew and Luke did not have Ancestry.com! Nor should we take these geneologies anachronistically, that is, by imposing our modern assumptions on them. For instance, to us geneology is about genetics, and we have difficulty appreciating how ancient Jews would view legal paternity. What really matters is to understand each evangelist's particular purposes in presenting Jesus' geneology as he did. It is in examing their particular purposes that we discover the Gospel in the geneology of Jesus.
One of Matthew's purposes is to see a relation between Abraham and Jesus. Matthew begins his geneology with Abraham. Abraham was the one to whom the LORD promised a people in whom all the families of the earth would be blessed. The promise to Abraham would now be fulfilled in Jesus. Thus Matthew's geneology is a signal that the history of God's salvation of the world would come to a climax in the event of Jesus Christ. This evangelical message is reinforced by Matthew's scheme of three sections of 14 generations: Jesus will recapitulate the whole history of Israel in its generations from Abraham to David, from David to the exile, and from the exile to the time of Jesus.
In the geneological lists Matthew found and used, he inserted the names of four women besides Mary: Tamar, Rahab, Ruth, and Bathsheba who is called 'the wife of Uriah." As Brown says (p. 78), "there is something extraordinary or irregular in their union with their partners--a union which, though it may have been scandalous to outsiders, continued the blessed lineage of the Messiah." The inclusion of the women highlights God's initative in the history of salvation and demonstrates "how God uses the unexpected to triumph over human obstacles." In this way, these women in the geneology foreshadow the role of Mary in the birth of Jesus the Messiah. Perhaps there is even a note of anti-patriarchalism by including this list of women in the naming of Jesus' ancestors. After all, the conception of Jesus by Mary includes no role for the male.
Luke traces his geneology back to Adam whom he calls "son of God." In Luke's geneology, Jesus' significance is located not only in the history of the chosen people of Israel, but also in the history of the whole human race. The Gospel in Luke's geneology is that Jesus is the true human being who fulfills the original purpose of the human race by being a "son of God," a person who lives in communion with the Creator, for he was the Son of God who became incarnate to restore the human race to its true nature.
A small, but perhaps not insignificant detail in both geneologies, is that both of them contain the names of ancestors both great and unknown. The unknown names matter as much as those of Abraham, David, and others since God's plan of salvation and purposes include all of us who spend our lives in historical obscurity. It is not given to every generation to live at a turning point in history, but every generation is essential for the continuation of life and of God's purposes.
Once we cease expecting Matthew and Luke to answer our modern questions and listen for what they themselves were trying to say, then we find rich insights into the ways in which divine purposes operate in the world. Indeed, in the geneology of Jesus we can even hear the Gospel of God's plan of salvation.