Challenge: The genealogies of Jesus in the book of Luke and Matthew are different. Atheists contend they contradict each other. How do you answer this objection?
Answer: There are multiple explanations for why the genealogies in the two Gospels are different. I will take the position the Matthew genealogy traces Joseph’s lineage and the genealogy from Luke follows the family line of Mary. I have multiple reasons for believing this is the best solution.
1. Doctor Luke said he researched extensively other writings before he wrote Acts and the book of Luke. His primary source of information was the Apostle Paul. Both of these men would have been well aware of the writings during their lifetime. Most New Testament scholars would say that the book of Matthew was written years before Luke. In fact they would say Mark was the first Gospel written. As part of his research Luke would have been very acquainted with the writings of both Mark and Matthew. In fact we see lots of shared materials amongst the three Gospels. Therefore, Luke would have known and likely studied the genealogy in Matthew’s writings. Why would Luke write another genealogy concerning the lineage of Joseph? And if it’s about Joseph, why is it so different? I believe the differences reflect the fact that Luke described the family line of Mary; even though her name doesn’t appear in the genealogy. My sense is her name is left out for cultural reasons. Almost all genealogies from that time period traced the family tree of men. Tracing Mary’s genealogy would have been highly unusual during that time period. A virgin birth would also have been highly unusual during any time period. We can ascertain it is Mary’s family tree because Heli is listed as the “father” of Joseph but he is really the father of Mary. Heli was Joseph’s “father in law.” The Jewish Talmud (ancient religious writings) identifies Mary’s father as Heli.
2. Matthew lists Jacob as the father of Joseph and Luke seems to also have Heli as the father of Joseph. This sounds like a contradiction. Key to understanding this dilemma is Luke 3:23 “When He began His ministry, Jesus Himself was about thirty years of age, being, as was supposed, the son of Joseph, the son of Eli.” In verse 23 Luke says Joseph is supposedly the father of Jesus. He is not the physical father of Jesus. The rest of Luke’s genealogy traces through the physical descendants. Joseph is the legal father through marriage but it is Mary who is the actual physical mother of Jesus. Matthew’s purpose for his Gospel was that he was writing to a Jewish audience and by tracing back to Abraham he was trying to establish Jesus as the coming Messiah and the fulfillment of the blessing from the Abrahamic Covenant. However, Luke was writing to a primarily gentile audience and he was tracing the physical line back to Adam to establish Jesus was fully human. In His humanity He could be the savior of the world. So both genealogies had a different purpose reflected in the many differences. The different purposes also explain why Matthew wrote about the line of Joseph and Luke Mary. A key piece of evidence to explain the different purposes is the Davidic Covenant.
In the Davidic Covenant, God promised David his kingdom that would have no end. Someone from his line would sit on the throne forever. From David’s family line a child, yet to be born would succeed him and establish his kingdom. 2 Sam 7:12-17 “I will raise up your descendant after you…and I will establish the throne of his kingdom forever.” The immediate reference (v 12-15) refers to Solomon, who will build the temple instead of David. Yet the promise also looked to the future: “And your house and your kingdom shall endure forever; your throne shall be established forever.” (v16) In the future sense, this would be fulfilled in Jesus, who came to establish the Kingdom of God. Jesus was born in the city of David (Luke 2:4) and his ancestry was traced by Luke back to David (Luke 3:23-38). The Solomon connection was fulfilled when Joseph became of the father of Jesus through adoption.
Matthew traces his genealogy through David and his son Solomon to fulfill the Davidic Covenant. In contrast Luke’s genealogy goes through David’s son Nathan. Both family lines come from David. Luke, a physician and researcher, knew exactly what he was doing by providing a second genealogy of Jesus. His tracing the descendants through a different son of David also gives us a clue this is the line of Mary and not Joseph. Jesus then has a physical link to the line of David through Mary and through Solomon to Joseph we have a father who has legal status from adoption. The virgin birth excluded a physical father. Thus the Davidic Covenant was fulfilled.
3. An additional problem arises from the fact that King Jehoiakim (formerly Eliakim in 2 Kings 23:34) was so evil God said no physical offspring of his would sit on the throne (have a lasting reign). We read in Jeremiah 36:30-31 “Therefore thus says the LORD concerning Jehoiakim king of Judah, ‘He shall have no one to sit on the throne of David, and his dead body shall be cast out to the heat of the day and the frost of the night. 31 I will also punish him and his descendants and his servants for their iniquity, and I will bring on them and the inhabitants of Jerusalem and the men of Judah all the calamity that I have declared to them—but they did not listen.’'” This is a powerful judgment from God punishing the king of Judah. This seemed to be a major problem because Jehoiakim is from the line of Solomon and the future king of the Davidic Covenant is to be from the line of Solomon. How would this be resolved? Again the resolution involves Mary and Joseph. If we see the Luke genealogy as Mary’s then Jesus was her physical offspring from the line of David through Nathan. The problem of Jehoiakim being cursed by God and no physical offspring as king was solved when Jesus was not the physical offspring of Joseph but instead was his adopted son. Thus we have the complete fulfillment of the Davidic Covenant, in spite of the curse upon King Jehoiakim. God accomplished the impossible.
I believe I have answered the challenge. There are other solutions to this genealogy problem. However, it seems reasonable that if Luke was well aware of Matthew’s genealogy, he is not an idiot and he wouldn’t have written a competing genealogy. Most scholars view his writings as very scholarly and historians love what we today call the book of Acts. Most of the evidence points to the second genealogy as Mary’s. Plus we have no written objections from this time period to this second genealogy. If there was an obvious contradiction, people during Luke’s time would have objected and raised a fuss. And yet, we have no record of any objections.