Augustine of Hippo

For, saith He, in every kingdom the children are free, that is, not under tax. Much more therefore should they be free in any earthly kingdom, who are children of that very kingdom under which are all the kingdoms of the earth.

Catena Aurea by Aquinas ↗

Jerome

But that we may not offend them: go to the sea, and cast in a hook, and that fish which shall first come up, take: and when thou hast opened its mouth, thou shalt find a stater: take that, and give it to them for me and thee. What I should first admire in this place, I know not, whether the foreknowledge, or the greatness of the Saviour. The foreknowledge that he knew the fish would have a stater in its mouth, and that he himself would be the first to be caught. …

Commentary on Matthew ↗

Thomas Aquinas

And he said: from strangers. Then Christ's response is presented, because kings spare their own sons. Isaiah 3:15: why do you crush my people, and grind the faces of the poor? For it seems just. For he who presides ought to have care of his subjects; therefore his subjects ought to serve him as members serve the body. For just as the members of the body serve the whole body from what is their own, so every subject from his own goods ought to serve the community. Therefore the Lord concludes: then the children are free. …

Commentary on Matthew ↗