Ruth's Inclusion

Quomodo enim Ruth, cum esset alienigena, Judaeo nupsit? Et qua ratione in Christi generatione ejus putavit evangelista copulae commemorationem esse faciendam, quae Legis serie vetabatur. Non ergo ex legitima Salvator generatione manavit? Videtur esse deforme, nisi ad Apostolicam sententiam revertaris, quia lex non est justis posita, sed injustis. Haec enim cum sit alienigena et Moabitis praesertim cum lex Moysi prohiberet has nuptias, Moabitasque excluderet ab Ecclesia; sic enim scriptum est: Moabite non introibunt in Ecclesiam Domini usque ad tertiam et quartam generationem, et usque in saeculum, quomodo intravit in Ecclesiam, nisi quia sancta et immaculata moribus supra legem facta est, Si enim Lex impiis et peccatoribus postia est, utique Ruth, quae definitionem Legis excessit, et intravit in Ecclesiam, et facta est Israelitis, et meruit inter majores Dominici generis computari, propter cognationem mentis electa non corporis, magnum nobis exemplum est, quia in illa nostrum omnium qui collecti ex gentibus sumus, ingrediendi in Ecclesiam Domini figura praecessit. Hanc igitur aemulemur; ut quia haec moribus hanc praerogativam meruit adsciscendae societiatis suae, sicut historia docet: nos quoque propter morum electionem in Ecclesiam Domini, meritis suffragantibus, allegemur. Sanctus Ambrosius Mediolanensis, Expositio Evangelii secundum Lucam, Liber III Source: Migne PL 15.1601b-1602a

But how did Ruth who was a foreigner, marry a man who was a Jew? And why in Christ's genealogy did the Evangelist think to make mention of a union which was prohibited by the commandments of the Law? Was the Saviour not drawn from legitimate lineage? It appears monstrous to us unless we attend to that passage of the Apostle: 'The Law is not given for the righteous but the unrighteous.' 1 For this woman was an foreigner, a Moabitess, from a nation with whom the Law of Moses forbade all marriage and completely shut them out of the Church. So it is written, 'A Moabite shall not enter into the Church of God, even to the third and fourth generation, and even forever.' 2 How then did she enter into the assembly unless that she was holy and unstained in her life above the Law? If the Law was given for the impious and sinners, so Ruth, who exceeded the scope of the Law, entered into the assembly and took her place among the Israelites and merited to be reckoned among the great ones of the lineage of the Lord, on account of the elevation of her mind, not her body, being to us a great example, because in her was prefigured the entrance into the Lord's Church of all of us who are gathered out of the Gentiles. This, then, emulate, that as by her conduct she merited the right to be approved for this society, as the history teaches, so we also on account of the elevation of our conduct, by right of merits, be voted into the assembly of the Lord. Saint Ambrose, Commentary On The Gospel of Saint Luke, Book 3 1 1 Tim 1.9 2 Deut 23.3