And Joseph and his mother marveled at those things which were spoken of him.
All Commentaries on Luke 2:33 Go To Luke 2
Augustine of Hippo
AD 430
He however might be called His father in that light in which, he is rightly regarded as the husband of Mary, that is, not from any carnal connection, but by reason of the very bond of wedlock, afar closer relationship than that of adoption. For that Joseph was not to be called Christ's father was not, because he had not begotten Him by cohabitation, since in truth he might be afather to one whom he had not begotten from his wife, but had adopted from another.
Or by this is signified that Mary also, through whom was performed the mystery of the incarnation, looked with doubt and astonishment at the death of her Lord, seeing the Son of God so humbled as to come down even to death. And as a sword passing close by a man causes fear, though it does not strike him; so doubt also causes sorrow, yet does not kill; for it is not fastened to the mind, but passes through it as through a shadow.