So by means of the virgin Jewess Mary her firstborn son was born into the royal family of David, and by her Jesus had a fleshly natural right to David’s kingdom. In proof of this fact the apostle Paul was inspired to write about the good news from God: “Concerning his Son, who sprang from the seed of David according to the flesh, but who with power was declared God’s Son according to the spirit of holiness by means of resurrection from the dead​—yes, Jesus Christ our Lord.”​—Romans 1:1-4.

40. (a) What did Joseph feel obligated toward God to do respecting Mary’s son Jesus, thus conferring what upon Jesus? (b) Whose son does Luke call Joseph, and why?

⁴⁰ After Mary’s pregnancy was discovered, her intended husband was given an explanation and told to take Mary as his wife to his home for her. Joseph did so, there at Nazareth. He realized his obligation toward God to adopt God’s Son by Mary as his own firstborn son and thereby give Jesus the legal right to David’s throne, forasmuch as Joseph was a descendant of David through King Solomon.c (2 Samuel 7:13-16) This is what Joseph did by having Jesus circumcised on the eighth day of his birth and calling his name Jesus and also by presenting the babe Jesus on the fortieth day of his birth in purification rites for himself and Mary at the temple in Jerusalem. (Matthew 1:17-25; Luke 2:21-24) This is why he was called “the son of Joseph.” (John 1:45; 6:42) This is why, too, in Doctor Luke’s genealogy of Jesus Christ he says: “Furthermore, Jesus himself, when he commenced his work, was about thirty years old, being the son, as the opinion was, of Joseph, son of Heli.” (Luke 3:23)