Matthew 17:27

Lest we should offend them] i.e. 'lest we give the collectors, who do not know that I am the Son of God, the false impression that I dishonour the Temple, and so hinder their conversion, go thou,' etc. Offend] RV 'cause to stumble.' A piece of money] lit. 'a stater.' A silver stater was exactly four drachmæ or denarii, i.e. a shekel, enough to pay for two. For me and thee] not 'for us.' The two cases were different. In our Lord's case the payment was a condescension, in Peter's a debt.

There are many authentic historical instances of valuables being found inside fish. Polycrates, tyrant of Samos (6th cent. b.c.), threw into the sea an emerald signet set with gold, the work of the Samian artist Theodorus. A few days later his cook found the signet inside a large fish, which a fisherman had presented to the monarch.
Although the supernatural element in this miracle is not greater than in the other physical miracles, yet its dramatic character, and the absence of the motive of benevolence which so generally characterises our Lord's miracles, suggest to some critics that we have here not strict history, but a mixture of history and tradition, the nucleus of historic fact being that our Lord sent St. Peter to catch a fish, and that this fish, when sold, realised a shekel. This explanation of the incident is quite possible.