The Jewish background of the New Testament
Traditional Christian scholars have put forward various theories that seek to reconcile these two accounts. One common explanation for the difference is that Matthew recorded the legal genealogy of Jesus through Joseph, according to Jewish custom, while Luke, writing for a Gentile audience, gives the actual biological genealogy of Jesus through his mother Mary. This argument is problematic, however, because both Matthew and Luke clearly base their genealogies on Joseph.
This strange discrepancy in Joseph’s lineage is easily explained if one knows the Jewish background—the law of levirate marriage (Deut. 25:5). A childless woman whose husband died, had to be married to her husband's brother and the first-born son of such marriage would carry the name of the deceased brother. Thus, Joseph's natural father was Jacob who actually “begot” him (as written in Matthew), while his legal father was Eli (as given in Luke).
This is a wonderful example of how helpful and important the knowledge of Jewish background can be. The differences in the text of the Scriptures sometimes seems irreconcilable, but more often than not they are based on some background details that we are unaware of. Enroll in our course Jewish Background of the New Testament and you will be able to understand many inconsistencies in the Scripture.