42 for Matthew, 72 for Luke

In the first chapter of the Gospel of St. Matthew, the first 17 verses are given over to providing the genealogy of Christ. The sequence ends with this summation:

1:17: So all the generations from Abraham to David are fourteen generations. And from David to the transmigration of Babylon are fourteen generations. And from the transmigration of Babylon to Christ are fourteen generations.

That makes for 42 generations from Abraham to Christ.

Meanwhile, the Gospel of St. Luke begins its genealogy in the third chapter at the twenty-third verse. And St. Luke lists 72 generations from Adam to Christ.

A contradiction? Only a seeming one.

St. Matthew's primary audience was the Jewish Christians; St. Luke, the gentile Christians (beginning with the "most excellent Theopilus"). The latter was the missionary companion of St. Paul, the apostle to the gentiles.

In his genealogy St. Matthew demonstrated that Christ was the Messiah, the son of David. In the Hebrew language, David's name has three consonants, D-V-D; like Arabic, written Hebrew does not record vowels. In the Jewish tradition, the letters D-V-D were given the numerical significance of 4-6-4, which added together equals 14. Adhering to the Jewish custom, St. Matthew lists three sets of 14 generations -- or 42 generations -- of the Davidic line.

St. Luke arrived at his number based on the Jewish tradition that the whole world was occupied by 72 races of men; thus, by naming 72 generations, St. Luke demonstrated that Christ had come to bring salvation to all men.

Or again, St. Matthew gave the juridical succession through which Davidic rights descended to Joseph, and then to his legal son -- i.e. Jesus. St. Luke, meanwhile, abstracted from this legal or juridical succession, and followed the real genealogy according to consanguinity.