Glossa Ordinaria
Catena Aurea · Matthäusevangelium 1
Then Joseph her husband, being a just man, and not willing to make her a public example, was minded to put her away privily.
(part ap. Anselm. part in Ord.) Or, being unwilling to bring her home to his house to live with him for ever, he was minded to put her away privily; that is, to change the time of their marriage. For that is true virtue, when neither mercy is observed without justice, nor justice without mercy; both which vanish when severed one from the other. Or he was just because of his faith, in that he believed that Christ should be born of a virgin; wherefore he wished to humble himself before so great a favour.