Cyril of Alexandria

The stranger who comes before the Lord should not say, "The Lord will surely cut me off from his people." For it will not be because he is foreign in the sense of not having Israelite blood therefore that he will be without a share in the gifts from the Lord, the intimate and spiritual relationship with him. But if he clings to the Lord in his domestic affairs and his friendships, he will be made to belong in the holy people and to the royal priesthood and to the inheritance of God. He will be numbered among the children of Abraham. …

Commentary On Isaiah 5:3.56:3-5 ↗

Jerome

Because the Lord says these things to the eunuchs: If they keep my Sabbaths, and choose what I desire, and hold fast to my covenant, I will give them a place in my house and within my walls, and a better name than sons and daughters; I will give them an everlasting name that will not be cut off. …

Commentary on Isaiah ↗

Thomas Aquinas

Second, he sets out the universality of this utility: and let not the son of the stranger. And first, he excludes the desperation of some who seemed unworthy, either because of defect of race, because they were not of the race of Israel: that adheres to the Lord, keeping his precepts; saying: the Lord will divide and separate me from his people, not making me a sharer in the salvation promised to them: for there is no distinction of the Jew and the Greek: for the same is Lord over all (Rom 10:12). …

Commentary on Isaiah ↗