(In later chapters of Matthew, the term seems to touch on a tradition not directly connected with eschatology. In the OT, the term “son of David” is usually applied to Solomon (with one exception; 2 Samuel 13:1 = Absalom). The fact that Solomon is touted in later Jewish folklore as an exorcist and healer would not have escaped Matthew: in that part of the gospel, he often connects the term in context of exorcisms; cf. 9:27; 12:23; 15:22; 20:30-31.)
See the following for uses of “son of Abraham” to refer to Jewish blood: Luke 19:9; John 8; Acts 13:26; Mishnah, Baba Qamma 8.6. The phrase is also used to refer to one who is worthy of Abraham: cf. 4 Maccabees 6:17, 22; 18:23; Galatians 3:7; Talmud, Betzah 32b.
As the Savior of Israel, Jesus must be a true Israelite, and so Matthew traces His origin to Abraham. Because the Matthaean genealogy covers the period from Abraham to the Messiah it is natural to think of Jesus as the culmination of the history which began to Abraham. But there is probably more to Jesus’ being a “son of Abraham.” Abraham was a gentile by birth, and it is promised that “all the nations” will be blessed in him (Genesis 12:3; 18:18; etc.) In Jewish literature he was sometimes portrayed as “the father of many nations” (Genesis 17:5; 44:19; 1 Maccabees 12:19-21) or as the first proselyte (e.g. Talmud, Hagigah 3a); and the promise to Abraham was employed to further the purposes of Jewish mission. St. Paul also represents him as the true father of all believers, Jew and gentile alike (Romans 4:1-25; Galatians 3:6-29). Therefore the reference may also for Matthew serve to indicate that Jesus is also the Messiah for the gentiles.
The juxtaposition of the two terms “son of David” and “son of Abraham” is very intriguing since outside of Matthew, the promises made to the “seed” of Abraham and the “seed” of David are brought and conflated together (so in Luke 1:30-33, 55, 69-73; Acts 3:25; 13:23; also cf. Galatians 3:16; Jeremiah 33:21-22; Targum on Psalm 89:4). This perhaps also explains the juxtaposition: the “seed” of Abraham and the “seed” of David to whom the promises apply equals the Messiah.
Davies and Allison, in their commentary on Matthew, make three final points:
First, given Matthew’s emphasis on righteousness and upholding the Torah (5.17-20), the mention of Abraham is particularly apt, for the patriarch was revered as one who had been perfectly obedient to the commands of the Law. He indeed kept the whole Torah even before it was written. [Footnote 38: Ecclus 44.19-21; [URL=“http://quod.lib.umich.edu/cgi/r/rsv/rsv-idx?type=DIV1&byte=4216956”]Prayer of Manasseh 8; Jub. 6.19; 16.28; 21.2; 23.10; 2 Bar. 57.2; T. Abr. (A) 1; 4; m. Qidd. 4.14; b. B. Bat. 17a.] Secondly, there was a tradition that Abraham ‘discovered both astrology and Chaldean science’ (Ps. Eupolemus in Eusebius, Praep. ev. 9.17; cf. Artapanus in Eusebius, Praep. ev. 9.18; the Jewish mystical hymn in Eusebius, Praep. ev. 13.12; Josephus, Ant. 1.158, 167-8; LAB 18.5; b. B. Bat. 16b). [39: For rejection of this seemingly wide-spread tradition see Jub. 12.15-17; Philo, [URL=“http://www.earlychristianwritings.com/yonge/book22.html”]Sib. Or. 3.218-30; b. Ned. 32a. On the whole matter consult Hengel, Judaism and Hellenism 2, p. 62, n. 264, and C.R. Holladay, Fragments from Hellenistic Jewish Authors, Vol. 1: Historians, Chico, 1983, pp. 180-1.] It is fitting then, that the ‘son of Abraham’ should be honoured by magi from the east (2.1-12). Finally, since the ‘son of Abraham’ in 1.1 is immediately followed in 1.2 by mention of Isaac, and since, as already suggested, ‘son of David’ may have had a double meaning for Matthew, referring to Jesus as both the Davidic Messiah and one like Solomon, it is just possible, one might urge, that ‘son of Abraham’ could also have a double meaning, designating Jesus not only as a descendant of Abraham but as one like Isaac, who carried wood on his back and was willing to give up his life in obedience to God (cf. Rom 8.32?). [40: If, as has sometimes been urged, there was a tradition about the virgin birth of Isaac (see on 1.23), this would certainly buttress such a conjecture.] Yet nowhere else in the First Gospel is Jesus clearly associated with Isaac (although see on 3.17).