Some people may be aware of the fact that the genealogies in the Gospels of Matthew and Luke are not identical to each other. If you look closer, they are not even in harmony with each other. Matthew works forward and Luke works backward. When you align the genealogies, you’ll see that Matthew starts with Abraham, and where that genealogy meets with Abraham in Luke’s Gospel, they are harmonious through 13 generations. At that point, Luke’s Gospel follows David’s son Nathan, while Matthew’s Gospel follows Solomon in the line of kings. They split for 13 generations, where they come together with Shealtiel and Zerubbabel, around the time of the exile. Then they diverge again until meeting again with Joseph.

A couple of things to point out:

1. This doesn’t look like a simple error. It would be one thing if in the long list of names there were a couple that were off. That is not the case here. These two lists follow almost entirely different genealogies from the time of David, and they have completely different numbers of generations.
2. Biblical genealogies leave out generations—sometimes numerous generations. For example, the amount of time spoken of between Obed and David is a few hundred years. There was pretty certainly more than three generations in that time. This is a variable that can be very difficult to account for.
3. There are three main theories for why these diversions exist.

Divergence theory 1: the genealogies of Mary and Joseph

Some people find this very difficult to believe since both genealogies in Matthew and in Luke seem to claim that Jesus is the son of Joseph. However, Luke does focus much more on Mary as his main character in the early chapters of his Gospel. Chapter 3 serves as a division from the beginning section in which Mary is a main character to the focus on Jesus in the rest of the book. So, thematically, a genealogy of Mary in Luke chapter 3 would make sense.

Luke 3:23 says that Jesus was “the son, so it was thought, of Joseph, the son of Heli.” There is a fairly long tradition of interpreters who think that the phrase “so it was thought” is meant to indicate that Jesus was in fact not the son of Joseph, and that his father is credited as Heli in terms of his physical ancestry. The argument is that since Jesus didn’t have an earthly, human father involved in his conception, the closest physical father would have been the father of his mother, who was, presumably, Heli.

So, if we pay attention to the way Luke is writing his Gospel thematically, and if we take note of the strange idiom related to Joseph’s fatherhood, then this view has credibility as a possible solution.

Divergence theory 2: Joseph had two fathers

Okay, this possibility definitely sounds even weirder than the last; but there are at least three ways this could work out, with only two that would be relevant to a biblical genealogy.

1. One genealogy refers to Joseph’s stepfather. However, this option is virtually impossible. As we’ll find out in the third option, this isn’t the way genealogies were reckoned in the ancient world. Stepfathers didn’t get to count their children as part of their line. It actually worked in the reverse direction through a legal system called “levirate marriage.”
2. Joseph was adopted into a childless family. Some have suggested that Mary had no brothers, and so there were no men in her father’s line. Legally, her father could have adopted Joseph, allowing a line to be reckoned through Joseph though it was physically the line of Mary. If this is true, then what is essentially Mary’s lineage would be credited as Joseph’s lineage, even though Joseph would have a second lineage that could be recorded in Matthew’s Gospel.
3. Joseph has two fathers through levirate marriage. Most modern people are not familiar with the biblical commands of levirate marriage (see Deuteronomy 25:5). Levirate marriage was explicitly created to carry on multiple family lines through one man. This happened if, and only if, a man were to die who had married but had produced no children with his widow. This would leave a widow without children and a man without a lineage. In such cases, the surviving brother was required to take the widow as an additional wife or as his first wife and have children “for his brother.” These children were credited into the family line of the deceased brother, but were still legitimately physically children of the brother who had engaged in the levirate marriage. In this sense, you would have a “legal” and a “physical” lineage for the same person.

How would levirate marriage explain Jesus’ genealogy?

Imagine Jacob and Heli (the men listed as Joseph’s fathers in the Gospels of Matthew and Luke, respectively) were brothers. Assume Heli married a woman named Esther. Now assume Heli died without having any children with Esther. Jacob would have then been responsible to marry Esther and seek to have children both for her provision in old age and to carry on the genealogy of his brother. These children physically came from Jacob, and so they were physically in his lineage. The children could have been reckoned either way for a genealogy. However, for the purposes of legal property rights, they were the children of Heli and not Jacob.

This same scenario could have been in the reverse: Jacob could have been the one who died and left the widow, and Heli could have married that widow and had children. However, either situation only solves the question of Jesus’ genealogy if Heli and Jacob were half brothers who shared a mother and not a father. Otherwise they would be in the same genealogical line.

This argument may seem fairly far-fetched to the modern reader, but it is possible. People more often died early in other places and times in the world. The idea that in two generations there could have been two deaths or a divorce is not that strange. For example, most biblical scholars believe that Joseph had died by the time of Jesus’ crucifixion. In John’s Gospel Jesus tells Mary, “behold your son,” and John, conversely, “behold your mother,” so that John would take responsibility to care for his widowed mother. Life was tough in those days. A recent example: on Easter, I was with a middle-aged woman from central Africa who has had three of her 8 children die before her. And so this scenario isn’t as strange as it might first strike people now in America or other developed nations.

Divergence theory 3: royal versus physical lineage

Another possibly theory is that Matthew presents the royal line of descent from David, listing the names of the heirs to the throne, and therefore emphasizing Jesus as King. In contrast, Luke gives the actual descendants of David and therefore the physical descendants of Joseph. However, this doesn’t completely answer the question of the differing fathers of Joseph presented between the two Gospels, unless combined with another one of the theories.

Of course, there is a fourth option:

The Gospel writers could have just been wrong and made these genealogies up. But why include a made up genealogy? To begin with, it’s very likely that the genealogy of Jesus was already circulating and that either Matthew or Luke were conscious of the work of the other before they published their work. Additionally, the two genealogies are not even close to each other. It’s not like there are a couple of inconspicuous differences. The lists are two completely different genealogies that are each very detailed and decisive. I think this fourth option is not just a spiritual cop-out, but an intellectual cop-out as well.

So, which one is it?

I think it is most likely that the first divergence theory is true: Luke is a genealogy of Mary, crediting Jesus’ male physical heritage to Mary’s father. Luke is a doctor, so this seems like it would be logical to him. He also makes Mary his main character in his Gospel, plus he includes the odd Greek phrase about Joseph. So that’s my bet.

Always remember, history is a complicated business that we are always incredibly simplifying for communication’s sake. If you include more, you have to explain more—and people also had to be brief when writing on woven plants (papyri). Paper was incredibly expensive. When reading ancient histories, we have to keep this in mind. Additionally, the Gospels were written to be copied and widely disseminated. Because of these reasons, they had to be short. This is a problem that Josephus and other writers of larger library works didn’t have to think about.

I hope this helps you think through this Biblical difficulty, and I hope it helps you realize that many passages that are attacked by skeptics aren’t nearly the problem that is often claimed.

Articles for further research:

1. http://www.newadvent.org/cathen/06410a.htm
2. https://zondervanacademic.com/blog/why-are-jesus-genealogies-in-matthew-and-luke-different/