Ante-Nicene Fathers, Vol VIII:
Apocrypha of the New Testament.: Chapter 11

Chapter 11.

And when he was thinking of rising up and hiding himself, and dwelling in secret, behold, on that very night, the angel of the Lord appeared to him in sleep, saying:  Joseph, thou son of David, fear not; receive Mary as thy wife:  for that which is in her womb is of the Holy Spirit.  And she shall bring forth a son, and His name shall be called Jesus, for He will save His people from their sins.  And Joseph, rising from his sleep, gave thanks to God, and spoke to Mary and the virgins who were with her, and told them his vision.  And he was comforted about Mary, saying:  I have sinned, in that I suspected thee at all.