After the events at Christ’s birth, and her receiving a special message from the angel that her child would be the Son of God, it is absurd to say that Mary was taken by surprise. As for the brethren of Jesus, He had no brethren in the first degree. Any relatives, even in the third or fourth degree, or even in the same tribe, were entitled brethren by the Jews. And of course some of these were surprised, unless we are to suppose that God made a special revelation to each one of them concerning Christ The Jews generally were surprised because they had built up in themselves despite the prophecies so very different a concept of the coming of the Messiah.
Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty