The gospels of Matthew and Luke each provide a paternal family lineage to demonstrate that Jesus was a descendant of King David, but these genealogies have three problems:
1) they conflict with each other on whether Joseph (Jesus' "father") descended from David through Solomon or Nathan,
2) Luke 3:35 follows the Septuagint and contains an extra name, conflicting with the list in the Hebrew Genesis, and
3) the genealogies do not logically matter anyway if Joseph was not really Jesus' father (i.e. Virgin birth), although when they were originally fabricated the virgin birth stories had probably not been invented yet.
Since the Messiah was to be a descendant of David, the Gospel writers or others preceding them thought they had to "prove" the genetic link. Obviously, the different writers neglected to consult each other on Jesus lineage, giving us another clue to the story's fabricated nature.Compare the genealogies of Jesus offered by the writers of "Matthew" and "Luke."
The passages in question are Matthew 1.1-17 and Luke 3.23-38.
Surface similarities and differences?
Surface Similarities:
Both claim Jesus was descended from David.
Each genealogy traces Jesus' lineage through Joseph.
Surface Differences:
Matthew 1 starts at Abraham and works down to Jesus in 3 sets of 14 generations. Luke 3 starts with Jesus and Joseph and works backward in time all the way to "Adam, son of God."
Matthew, by emphasizing Abraham and David provides a more Jewish world-view. Luke, by going back to Adam and God, displays a more universalist world-view.
Who are Joseph's father, grandfather, great grandfather?
Mt: Joseph's father is Jacob, son of Matthan, son of Eleazar.
Lk: Joseph's father is Heli, son of Matthat, son of Levi.
Do both trace Joseph's descent through David?
Yes, but by different pathways.
Mt: Jesus is descended from David through his son Solomon and his grandson Rehoboam.
Lk: Jesus is descended from David through his son Nathan and his grandson Mattatha.
Both genealogies make use of special numbers, multiples of 7.
Matthew has 3 sets of 14 generations from Abraham to the messiah. This could be interpreted as six 7's leading up to the messiah.
Luke has 77 generations of humans from God to Jesus through Adam.
Problems:
The genealogies disagree on the lineage of Jesus, which suggests that one or both of them was/were fabricated as Christianity developed, in an attempt to support certain claims.
Both trace Jesus' lineage through Joseph. This may have been fine in the earlier days of the religion, when at least certain groups of Christians may well have believed Jesus was actually Joseph's son, but the eventual development of the concept of the virgin birth voided the blood link which the genealogies had originally been written to provide. The genealogies, then, appear to have developed before the concept of the virgin birth, at a time when Jesus was considered a regular man with a human father, the son of Joseph. Some Christians had thought it important to 'prove' that Jesus was descended from David, so that they could claim he fulfilled various Jewish messianic expectations.
Both genealogies use multiples of 7, placing them ostensibly in the category of fabricated, as opposed to historical, genealogies. The earliest and most fictitious Old Testament genealogies almost always made use of 7, 10, and/or 12, numbers common in the ancient mythologies of many cultures. (See my paper "Numerology: The Use of Special Numbers in the Bible and Other Ancient Myths.")
Luke's genealogy comes from and reinforces a pre-scientific Jewish idea of the relatively young age of humanity. Jews and Christians living before the advent of modern science thought humans, along with the sky and land, had been created around 3760 to 4004 bce, by modern reckoning. That is why the author could suggest that there were really only 77 generations of humans from God to Jesus through Adam, a claim which is completely absurd, historically and biologically speaking. (See the section on Adam and Eve in my paper "Old Testament Chronological and Historical Problems.")
Christian apologists sometimes proposed that Luke's genealogy was really that of Mary, not of Joseph. It should be noted, however, that the text itself makes NO claim to offer Mary's genealogy. This apologetic proposal:
1. runs contrary to the text itself.
2. has no supporting evidence.