To prove Davidic descent both Matthew and Luke give the genealogy of Joseph, useless were not Joseph the father of Christ.

The genealogy of Joseph was that of Mary also. They were kinspeople of the same Davidic stock. The Jews as a rule counted their generations only in the male line, and such a generation alone would appeal to the Jews for whom Matthew above all wrote. The same St. Matthew records that the angel told Joseph that the child was conceived miraculously by the Holy Ghost and not through the intervention of man. St. Luke in turn left no doubt as to his mind on the subject when he carefully wrote that “Jesus himself was beginning about the age of thirty years; being (as it was supposed) the son of Joseph.” III., 23.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty