Two passages of Scripture give us information about the siblings of Jesus. Matthew 13:54–57 says, “Coming to his hometown, he began teaching the people in their synagogue, and they were amazed. ‘Where did this man get this wisdom and these miraculous powers?’ they asked. ‘Isn’t this the carpenter’s son? Isn’t his mother’s name Mary, and aren’t his brothers James, Joseph, Simon, and Judas? Aren’t all his sisters with us? Where then did this man get all these things?’ And they took offense at him.” Although we are not sure how many sisters Jesus had, the fact that He did indeed have at least six siblings is indisputable (Mark 6:3).
Jude 1:1 identifies the author of the epistle as “the brother of James.” This James is believed to be the James who wrote the book by that name, and who was also Jesus’ brother (see Galatians 1:19). Both James and Jude (Judas) would have been among the group of siblings who were at first embarrassed by their older brother’s audacious celebrity and came to take Him home (Matthew 12:46). James and Jude did not believe Him to be the Son of God until after His resurrection. But when they witnessed Jesus alive again, His siblings became ardent disciples.
Some have theorized that the Greek words adelphos (“brothers”) and adelphai (“sisters”) in Matthew 13 refer to spiritual brothers and sisters. Others, who hold to the idea of Mary’s perpetual virginity, assume that the references to Jesus’ siblings simply mean that Joseph had children of his own, before his marriage to Mary. However, there is no biblical support for either theory, and we have no logical reason to believe that the siblings mentioned by name in Scripture were not the biological children of both Mary and Joseph. We are never told exactly how many siblings Jesus had, but Mark 6:3 indicates there had to have been at least six: at least four brothers, named; and at least two sisters, unnamed.