Why did Luke place his genealogy of Jesus at this point in his Gospel? Probably he did so because this was the beginning of Jesus' public ministry. Matthew recorded Jesus' genealogy to show that He had a legitimate right by birth to occupy the Davidic throne. Consequently he placed his genealogy at the very beginning of his Gospel. Luke wanted to show the ancestry of Jesus, who now began His ministry, as the authenticated Son of God.
There are several other distinct differences between the two genealogies. They proceed in different directions, Matthew's starting with Abraham and ending in Jesus and Luke's beginning with Jesus and working back to Adam and God. Matthew's list stressed Jesus' place in the Jewish race by recording Jesus' ancestry back to Abraham, the father of the Jews. Luke's perspective is broader tracing Jesus all the way back to Adam and showing Him to be a member of the human race. Matthew grouped his names into three groups of 14 names each whereas Luke simply listed 78 ancestors.139Matthew recorded Jesus' descent from Joseph through Solomon, but Luke traced other ancestors from Joseph to David's other son Nathan. Matthew apparently gives Jesus legal line of descent from David naming the heirs to his throne, but Luke gave another branch of David's family tree that seems to be Joseph's blood line.140Matthew mentioned several women in his genealogy, but Luke mentioned none. Finally Luke's list is considerably longer than Matthew's.
"The significance of the genealogy in Luke probably lies in the emphasis on Jesus as a member of the human race, a son of Adam; in the contrast of Jesus, the obedient Second Adam (a theme implicit but not explicit in Luke), with the disobedient first Adam; and in Jesus as the true Son of God (cf. Adam,' v. 38)."141
Luke also stressed the universal significance of Jesus for the whole human race, not just for the Jews, by tracing His ancestry back to Adam. This theme, too, is prominent in the third Gospel.
3:23 Luke probably used the round number "30"to describe Jesus' age when He launched His ministry because many significant Old Testament characters began their service of God when they were 30 (cf. Gen. 41:46; 2 Sam. 5:4; Ezek. 1:1). This included Israel's priests (Num. 4). Evidently Jesus was 32 years old when He began His ministry.142Luke also clarified that Jesus was not the physical son of Joseph. People only supposed that He was.
3:24-38 Matthew traced Joseph's line back to David through Joseph's father Jacob and David's son Solomon. Luke traced Joseph's line back to David through Joseph's father Eli (or Heli, NIV) and David's son Nathan. Is there a mistake in the text, is one of these genealogies really the genealogy of Mary rather than Joseph, or did Joseph have two fathers?
The two lines of Joseph proceed back through two entirely different sets of names. Therefore there does not seem to be an error in the text regarding the name of Joseph's father. Luke did not even mention Mary in his genealogy, and Matthew seems clearly to have been describing Joseph's ancestors (Matt. 1:16). Consequently it appears unlikely that one of the genealogies is Mary's. As strange as it may seem, Joseph appears to have had two fathers.
The custom of levirate marriage in the ancient Near East permitted the widow of a childless man to marry his (unmarried) brother. It was common to consider a child of the second marriage as the legal son of the deceased man to perpetuate that man's name. In genealogies the ancients sometimes listed such a child as the son of his real father but at other times as the son of his legal father. This may be the solution to the problem of Joseph's fathers. It is a very old explanation that the third century church father Africanus advocated.143Either Jacob or Eli (Heli) was Joseph's real father, and the other man was his legal father. This may also be the solution to the problem of Shealtiel's two fathers (Matt. 1:12; Luke 3:27). It is only an adequate explanation, however, if Jacob and Eli were half-brothers, specifically the sons of the same mother but not the same father. Jacob's father was Matthan and his grandfather was Eleazar whereas Eli's father was Matthat and his grandfather was Levi.
Another solution is that Matthew provided a list of incumbents (actual or potential) to the Davidic throne, and Luke listed Joseph's physical father and forefathers.144According to this view Matthew showed that Jesus had a legitimate right to rule as Messiah since He was in the royal line through His adoptive father Joseph. Luke showed that Jesus was a real blood descendant of David. Yet Luke had already showed in chapters 1 and 2 that Jesus was not a biological son of Joseph. Advocates of this view point out that Luke was careful to state that Jesus was only supposedly the son of Joseph (v. 23). However if He was not the physical son of Joseph what is the point of tracing Joseph's ancestors to prove Jesus' humanity? This criticism applies to the former view too.
Another view is that the genealogy is Joseph's, but Luke did not mean that Joseph was Jesus' physical father.
"In the eye of the law Jesus was the heir of Joseph; and therefore it is Joseph's descent which is of importance."145
Yet the purpose of the genealogy seems to be to trace Jesus back to the first man to prove that He was a real son of Adam.
The obvious problem with the view that Luke recorded Mary's genealogy is that he did not refer to Mary but wrote that his genealogy was Joseph's. One advocate of this view explained the lack of reference to Mary this way. It was not customary among the Romans or the Jews to include the name of a woman in such a list.146Nevertheless Matthew mentioned four women in his genealogy, and Luke showed more interest in women than any of the other evangelists.147It seems unlikely that he would have refrained from using Mary's name if he meant that this genealogy was hers.
Most of the scholars are not dogmatic about the solution to this problem.
"It is only right, therefore, to admit that the problem caused by the existence of the two genealogies is insoluble with the evidence presently at our disposal."148
From David to Abraham (vv. 32-34), Luke's list parallels Matthew's quite closely (Matt. 1:2-6). The list from Abraham to Adam (vv. 34-38) is very similar to the one in Genesis 11:10-26 (cf. Gen. 5:1-32; 1 Chron. 1:1-26).149
The presence of Shealtiel and Zerubbabel in the lists of both Solomon and Nathan's descendants is another problem (Matt. 1:12; Luke 3:27). King Jeconiah, a descendant of Solomon, may have adopted Shealtiel, a descendant of Nathan and Zerubbabel's father, into his line (cf. 1 Chron. 3:17; Jer. 22:30). Then Zerubbabel's descendants continued the two lines of Solomon and Nathan, one branch of the family perpetuating the legal line of Solomon and the other the blood line of Nathan.150Another possibility is that there were two sets of fathers and sons named Shealtiel and Zerubbabel, one set in Joseph's legal line and the other in his blood line.
