I wrote this post originally for the CCK Reason Blog here: http://www.cck.org.uk/reason/why-are-genealogies-christ-matthew-11-17-and-luke-323-38-different
However, these genealogies can be better understood with some general background information:
Biblical genealogies have different properties from the family trees that we are familiar with today.
Firstly, Biblical genealogies use the terms ‘son’ and ‘father’ loosely. They can mean either direct descendant or distant descendant. For example, we read in Luke 3:8 and John 8:39 that a group of religious teachers said to Jesus, ‘Abraham is our father’, which is absurd in the modern sense, since Abraham lived thousands of years before. Similarly, Jesus is described throughout the New Testament as ‘the son of David’ (Matthew 1:1), who lived hundreds of years before Jesus was born.
Secondly, due to the first point, some Biblical genealogies skip generations. Matthew 1 records three sets of 14 generations from Abraham to Christ, which we know cannot be literal by reference to other parts of the Bible. For example, Matthew reads ‘Joram fathered Uzziah’, which skips three generations according to 2 Chronicles 21:4 – 26:33.
The book of Matthew was written specifically to Jews. This can be deduced by the frequency the Old Testament is cited, and to which the Gospel writer explains how Old Testament prophecy was fulfilled in Christ. This would have been particularly important to Jews, as they did, and still do, consider the Old Testament the sacred Word of God. (1)
The genealogy in Matthew, then, is specifically written for Jewish readers. Therefore it is not surprising that it follows the royal line of Israel. Many of the Kings of Israel are mentioned in this genealogy, which are recorded in the Chronicles of Israel. This was an important point to establish, as the ‘Messiah’ (Anointed) in Jewish Old Testament prophecy would be of the line of David (The famous King of Israel). Equally, the genealogy is split into three sets of 14 because 14 symbolises completeness or perfectness (3). In addition, the Hebrew letters comprising the name ‘David’ have a numeric value of 14. Though a subtle point, this symbolism would not have been lost on 1st Century Jews (9). It would have also made it easier to memorise, which was a central part of Jewish tradition with regards to the scripture, and other important texts of the time. As written text was not as readily available as today, memorisation was an important part of religious and spiritual education.
The book of Luke was written for Theophilus, who is believed to have been a prestigious person, due to his address ‘most excellent Theophilus’. The Gospel of Luke was written in Koine Greek (Common Greek), and Luke himself was a Gentile (non-Jew) born in Antioch (5), which is why his work conforms to Greek literary norms, which in turn renders his book more accessible to Greek readers. (As Greek was the international language of the day).
As Luke is written to a Gentile audience, it is natural that Luke’s genealogy starts with Adam (The first man, from whom all nations descend) instead of Abraham (from whom the nation of Israel descended). Luke is emphasising the humanity of Christ, and his relevance to all the nations, compared to Matthew, who is specifically interested in Jewish lineage. It was necessary to stress the equal standing of Christians despite their various ethnic backgrounds, as Jewish feeling towards non-Jews in the 1st century was generally negative, and this undercurrent could sometimes be felt in the early church. (An ethnic distinction not found in the teachings of the apostles, for example: Acts 10, Acts 22:21, Acts 15:1-31, Galatians 2:11-16.)
Theories surrounding Matthew and Luke’s genealogies
The first argument suggests that Luke records the line of Mary, while Matthew records the line of Joseph. This is likely, due to a few factors: Firstly, that ‘Heli father of Joseph’, in Luke, is recorded to have been the father of Mary in the Jewish Talmud (4, 1). Joseph could have been considered Heli’s son at marriage, J. Stafford Wright explains:
Mary's father (Heli) had two daughters, Mary and the unnamed wife of Zebedee (John 19:25; Matt 27:56). If there were no sons, Joseph would become son of Heli on his marriage, to preserve the family name and inheritance (cf. Num 27:1-11; 36:1-12, esp. v. 8, which accounts for Mary marrying a man of the family of David.) (6)
Secondly, examining Luke 3:23, ‘being the son (as was supposed) of Joseph, the son of Heli’ Arnold G. Fruchtenbaum writes: That same Greek phrase could easily be translated in a different way. While all of the names in Luke’s genealogy are preceded with the Greek definite article, the name of Joseph is not. Because of this grammatical point, that same verse could be translated: "being the son (as was supposed of Joseph) the son of Heli." In other words, the final parenthesis could be expanded so that the verse reads that although Jesus was supposed or assumed to be the descendant of Joseph, He was really the descendant of Heli. The absence of Mary’s name is quite in keeping with Jewish practices on genealogies, and it was not unusual for a son-in-law to be listed in his wife’s genealogy.(8)
However the meaning of the Greek is disputed (7). Therefore, another theory suggested is that Luke’s genealogy also follows the line of Joseph as well as Matthew, but that Luke follows Joseph’s legal parentage, which is feasible due to the possibility that Joseph was legally the son of Heli through Mary (as discussed above). Considering that Luke’s genealogy starts many years before Matthew’s, there would also be significant gaps between the generations recorded, which would again account for the different names mentioned.
As we can see above, the respective accounts of Matthew and Luke were written to make very different points, to convince different audiences. Matthew was written to reason with Jews that Jesus fulfilled the prophetic criteria of the Old Testament, whereas Luke is not so concerned with such things. As a result he pursues Jesus’ lineage with respect to Adam.
In conclusion, a brief study of the form and context of these genealogies provide a basis for believing in the uniformity and historical accuracy of the Bible.
3. Mathews, Kenneth. ‘Are Biblical Genealogies Reliable?’, The Apologetic Study Bible, Holman, 2007, p.14
5. Bruce, F, F. The New Testament Documents: Are they reliable?, 1943, Inter-Varsity Press
6. J. Stafford Wright in Dict. of New Test. Theol., III. 662 (quoted in 2)