Albert Barnes Commentary Matthew 17:24

"And when they were come to Capernaum, they that received the half-shekel came to Peter, and said, Doth not your teacher pay the half-shekel?" — Matthew 17:24 (ASV)

And when they were come to Capernaum. (See Barnes on Matthew 4:13).

They that received tribute. In the original, this refers to those who received the two drachms. The drachm was a Greek coin, worth about 12 1/2 cents [about 7d.] of our money. This tribute, consisting of these two drachms, was not paid to the Roman government but to the Jewish collectors for the use of the temple service. Two drachms were about equal to half a shekel.

It was permitted in the Law of Moses that, when numbering the people, half a shekel should be received from each man for the services of religion. This was in addition to the tithes paid by the whole nation and seems to have been considered a voluntary offering. It was devoted to the purchase of animals for the daily sacrifice, wood, flour, salt, incense, etc., for the use of the temple.

Doth not your master pay tribute? This tribute was voluntary, and they therefore asked him whether he was in the habit of paying taxes for the support of the temple. Peter replied that it was his custom to pay all the usual taxes of the nation.