The Greek noun agkistron (Ἄγκιστρον) refers to a fishhook — the curved hook used to catch fish. It appears only once in the New Testament, in Matthew 17:27, where Jesus instructs Peter to cast a hook into the lake and retrieve the first fish caught, whose mouth would contain a coin sufficient to pay the temple tax for both of them.
The agkistron — the fishhook — features in one of Jesus' most intimate and quietly miraculous acts. Having established that as the Son of God He was not obligated to pay the temple tax (the sons are exempt), Jesus nonetheless chose to pay it "so that we may not cause offense" (Matthew 17:27). He then directed Peter — the fisherman — to use his familiar craft and find the provision miraculously waiting. The theology here is layered: Jesus fulfills obligations He transcends; He provides through the ordinary skills of His disciples; and His sovereignty encompasses even the sea and its creatures. The coin in the fish's mouth recalls the Creator's absolute sovereignty over creation. Peter's fisherman's hook became the instrument of miraculous provision — a reminder that God uses our ordinary tools for extraordinary purposes.