John 19:26-7
“Behold your son... behold your mother.”
3. And He, having committed His mother to John, said, “Behold your Son.” O the honor! With what honor did He honor the disciple! When He Himself was now departing, He committed her to the disciple to take care of. For since it was likely that, being His mother, she would grieve, and require protection, He with reason entrusted her to the beloved. To him He says, “Behold your mother.” This He said, knitting them together in charity; which the disciple understanding, took her to his own home. “But why made He no mention of any other woman, although another stood there?” To teach us to pay more than ordinary respect to our mothers. For as when parents oppose us on spiritual matters, we must not even own them, so when they do not hinder us, we ought to pay them all becoming respect, and to prefer them before others, because they begot us, because they bred us up, because they bare for us ten thousand terrible things. And by these words He silences the shamelessness of Marcion; for if He were not born according to the flesh, nor had a mother, wherefore takes He such forethought for her alone?
Source: Homilies on the Gospel of John (New Advent)