Cyril of Alexandria

For a lowly appellation is given to the Word whose origin is from God, that he is called slave, that is, a household member. For such a title can sometimes indicate "son," and at other times, as we have said, "household member." In the economy of the flesh, it is appropriate to consider the Son as a slave. For he is God by nature and free as being from God the sovereign Father, yet he took the shape or form of a slave. …

Commentary On Isaiah 4:4.49:5-6 ↗

Jerome

And now says the Lord, who formed me as his servant from the womb, to bring Jacob back to him, and Israel will not be gathered: and I am glorified in the eyes of the Lord, and my God has become my strength. And he said: It is not enough for you to be my servant to raise up the tribes of Jacob and to restore the remnants of Israel. Behold, I have given you (Vulg. Behold I have given you) as a light to the Gentiles, that you may be my salvation to the end of the earth. …

Commentary on Isaiah ↗

Thomas Aquinas

Concerning the first, he does two things. First is set out the claim of the prophet who puts forth his labor in preaching, even though, due to the fault of those who heard it, it bore no fruit, and he concludes: therefore my judgment, for myself, is with the Lord, before him, and my work with my God, as though pleasing to him: the founder has melted in vain (Jer 6:29). Second, he sets out the response of God: and now says the Lord. …

Commentary on Isaiah ↗