2 What then says Peter? "He says, Yea:" and to these indeed he said, that He pays, but to Him he said it not, blushing perhaps to speak to Him of these things. Wherefore that gentle one, well knowing as He did all things, prevented him,"saying, What do you think, Simon? Of whom do the kings of the earth take custom or tribute? Of their own sons, or of strangers;" and when he said "of strangers," He replied, "Then are the sons free."
For lest Peter should suppose Him to say so, being told it by the others, He prevents him, partly indicating what has been said, partly giving him leave to speak freely, backward as he was to speak first of these things.
And what He says is like this, "I am indeed free from paying tribute. For if the kings of the earth take it not of their sons, but of their subjects; much more ought I to be freed from this demand, I who am Son, not of an earthly king, but of the King of Heaven, and myself a King." Do you see how He has distinguished the sons from them that are not sons? And if He were not a Son, to no purpose has He brought in the example also of the kings. "Yea," one may say, "He is a Son, but not truly begotten." Then is He not a Son; and if not a Son, nor truly begotten, neither does He belong to God, but to some other. But if He belong to another, then neither has the comparison its proper force. For He is discoursing not of the sons generally, but of the genuine sons, men's very own; of them that share the kingdom with their parents.
Wherefore also in contradistinction He has mentioned the "strangers;" meaning by "strangers," such as are not born of them, but by "their own," those whom they have begotten of themselves.
And I would have you mark this also; how the high doctrine, revealed to Peter, He does hereby again confirm. And neither at this did He stop, but by His very condescension declares this self-same truth; an instance of exceeding wisdom.
For after thus speaking, He says, “But lest we should offend them, go thou and cast an hook into the sea, and take up the fish that first comes up, and you shall find therein a piece of money; that take, and give unto them for me and you.”
See how He neither declines the tribute, nor simply commands to pay it, but having first proved Himself not liable to it, then He gives it: the one to save the people, the other, those around Him, from offense. For He gives it not at all as a debt, but as doing the best for their weakness. Elsewhere, however, He despises the offense, when He was discoursing of meats, teaching us to know at what seasons we ought to consider them that are offended, and at what to disregard them.
And indeed by the very mode of giving He discloses Himself again. For wherefore does He not command him to give of what they have laid up? That, as I have said, herein also He might signify Himself to be God of all, and the sea also to be under His rule. For He had indeed signified this even already, by His rebuke, and by His commanding this same Peter to walk on the waves; but He now again signifies the self-same thing, though in another way, yet so as to cause herein great amazement. For neither was it a small thing, to foretell that the first, who out of those depths should come in his way, would be the fish that would pay the tribute; and having cast forth His commandment like a net into that abyss, to bring up the one that bore the piece of money; but it was of a divine and unutterable power, thus to make even the sea bear gifts, and that its subjection to Him should be shown on all hands, as well when in its madness it was silent, and when, though fierce, it received its fellow servant; as now again, when it makes payment in His behalf to them that are demanding it.
“And give unto them,” He says, “for me and you.” Do you see the exceeding greatness of the honor? See also the self-command of Peter's mind. For this point Mark, the follower of this apostle, does not appear to have set down, because it indicated the great honor paid to him; but while of the denial he wrote as well as the rest, the things that make him illustrious he has passed over in silence, his master perhaps entreating him not to mention the great things about himself. And He used the phrase, “for me and you,” because Peter too was a firstborn child.
Now as you are amazed at Christ's power, so I bid you admire also the disciple's faith, that to a thing beyond possibility he so gave ear. For indeed it was very far beyond possibility by nature. Wherefore also in requital for his faith, He joined him to Himself in the payment of the tribute.
Source: Homilies on the Gospel of St. Matthew (New Advent)