Ambrose of Milan
Catena Aurea · Matthäusevangelium 1
3–6. And Judas begat Phares and Zara of Thamar; and Phares begat Esrom; and Esrom begat Aram; and Aram begat Aminadab; and Aminadab begat Naasson; and Naasson begat Salmon; and Salmon begat Booz of Rachab; and Booz begat Obed of Ruth; and Obed begat Jesse; and Jesse begat David the king.
(ubi sup.) But how did Ruth who was an alien marry a man that was a Jew? and wherefore in Christ’s genealogy did His Evangelist so much as mention a union, which in the eye of the law was bastard? Thus the Saviour’s birth of a parentage not admitted by the law appears to us monstrous, until we attend to that declaration of the Apostle, The Law was not given for the righteous, but for the unrighteous. (1 Tim. 1:9.) For this woman who was an alien, a Moabitess, a nation with whom the Mosaic Law forbad all intermarriage, and shut them totally out of the Church, how did she enter into the Church, unless that she were holy and unstained in her life above the Law? Therefore she was exempt from this restriction of the Law, and deserved to be numbered in the Lord’s lineage, chosen from the kindred of her mind, not of her body. To us she is a great example, for that in her was prefigured the entrance into the Lord’s Church of all of us who are gathered out of the Gentiles.