A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
mat 17:22HEALING OF A DEMONIAC BOY--SECOND EXPLICIT ANNOUNCEMENT BY OUR LORD OF HIS APPROACHING DEATH AND RESURRECTION. ( = Mark 9:14-32; Luk 9:37-45). (Mat 17:14-23)
And while they abode in Galilee, Jesus said unto them--Mark (Mar 9:30), as usual, is very precise here: "And they departed thence"--that is, from the scene of the last miracle--"and passed through Galilee; and He would not that any man should know it." So this was not a preaching, but a private, journey through Galilee. Indeed, His public ministry in Galilee was now all but concluded. Though He sent out the Seventy after this to preach and heal, He Himself was little more in public there, and He was soon to bid it a final adieu. Till this hour arrived, He was chiefly occupied with the Twelve, preparing them for the coming events.
The Son of man shall be betrayed into the hands of men . . . And they were exceeding sorry--Though the shock would not be so great as at the first announcement (Mat 16:21-22), their "sorrow" would not be the less, but probably the greater, the deeper the intelligence went down into their hearts, and a new wave dashing upon them by this repetition of the heavy tidings. Accordingly, Luke (Luk 9:43-44), connecting it with the scene of the miracle just recorded, and the teaching which arose out of it--or possibly with all His recent teaching--says our Lord forewarned the Twelve that they would soon stand in need of all that teaching: "But while they wondered every one at all things which Jesus did, He said unto His disciples, Let these sayings sink down into your ears; for the Son of man shall be delivered," &c.: "Be not carried off your feet by the grandeur you have lately seen in Me, but remember what I have told you, and now tell you again, that that Sun in whose beams ye now rejoice is soon to set in midnight gloom." Remarkable is the antithesis in those words of our Lord preserved in all the three narratives--"The son of man shall be betrayed into the hands of men." Luke adds (Luk 9:45) that "they understood not this saying, and it was hid from them, that they perceived it not"--for the plainest statements, when they encounter long-continued and obstinate prejudices, are seen through a distorting and dulling medium--"and were afraid to ask Him"; deterred partly by the air of lofty sadness with which doubtless these sayings were uttered, and on which they would be reluctant to break in, and partly by the fear of laying themselves open to rebuke for their shallowness and timidity. How artless is all this!
mat 17:24THE TRIBUTE MONEY. (Mat 17:24-27)
And when they were come to Capernaum, they that received tribute money--the double drachma; a sum equal to two Attic drachmas, and corresponding to the Jewish "half-shekel," payable, towards the maintenance of the temple and its services, by every male Jew of twenty years old and upward. For the origin of this annual tax, see Exo 30:13-14; Ch2 24:6, Ch2 24:9. Thus, it will be observed, it was not a civil, but an ecclesiastical tax. The tax mentioned in Mat 17:25 was a civil one. The whole teaching of this very remarkable scene depends upon this distinction.
came to Peter--at whose house Jesus probably resided while at Capernaum. This explains several things in the narrative.
and said, Doth not your master pay tribute?--The question seems to imply that the payment of this tax was voluntary, but expected; or what, in modern phrase, would be called a "voluntary assessment."
mat 17:25He saith, yes--that is, "To be sure He does"; as if eager to remove even the suspicion of the contrary. If Peter knew--as surely he did--that there was at this time no money in the bag, this reply must be regarded as a great act of faith in his Master.
And when he was come into the house--Peter's.
Jesus prevented him--anticipated him; according to the old sense of the word "prevent."
saying, What thinkest thou, Simon?--using his family name for familiarity.
of whom do the kings of the earth take custom--meaning custom on goods exported or imported.
or tribute--meaning the poll-tax, payable to the Romans by everyone whose name was in the census. This, therefore, it will be observed, was strictly a civil tax.
of their own children, or of strangers--This cannot mean "foreigners," from whom sovereigns certainly do not raise taxes, but those who are not of their own family, that is, their subjects.
mat 17:26Peter saith unto him, Of strangers--"of those not their children."
Jesus saith unto him, Then are the children free--By "the children" our Lord cannot here mean Himself and the Twelve together, in some loose sense of their near relationship to God as their common Father. For besides that our Lord never once mixes Himself up with His disciples in speaking of their relation to God, but ever studiously keeps His relation and theirs apart (see, for example, on the last words of this chapter)--this would be to teach the right of believers to exemption from the dues required for sacred services, in the teeth of all that Paul teaches and that He Himself indicates throughout. He can refer here, then, only to Himself; using the word "children" evidently in order to express the general principle observed by sovereigns, who do not draw taxes from their own children, and thus convey the truth respecting His own exemption the more strikingly:--namely, "If the sovereign's own family be exempt, you know the inference in My case"; or to express it more nakedly than Jesus thought needful and fitting: "This is a tax for upholding My Father's House. As His Son, then, that tax is not due by Me--I AM FREE."
mat 17:27Notwithstanding, lest we should offend--stumble.
them--all ignorant as they are of My relation to the Lord of the Temple, and should misconstrue a claim to exemption into indifference to His honor who dwells in it.
go thou to the sea--Capernaum, it will be remembered, lay on the Sea of Galilee.
and cast an hook, and take up the fish that first cometh up; and when thou hast opened his mouth, thou shall find a piece of money--a stater. So it should have been rendered, and not indefinitely, as in our version, for the coin was an Attic silver coin equal to two of the afore-mentioned "didrachms" of half a shekel's value, and so, was the exact sum required for both. Accordingly, the Lord adds,
that take, and give unto them for me and thee--literally, "instead of Me and thee"; perhaps because the payment was a redemption of the person paid for (Exo 30:12) --in which view Jesus certainly was "free." If the house was Peter's, this will account for payment being provided on this occasion, not for all the Twelve, but only for him and His Lord. Observe, our Lord does not say "for us," but "for Me and thee"; thus distinguishing the Exempted One and His non-exempted disciple.