Money Changers
The money-changers appear in scripture only inside the temple precincts, and only as the target of an action by Jesus. Two passages — one early in his ministry, one late — describe the same kind of scene: tables overturned, coins poured out, and the temple traffic in animals and currency driven out by force.
The Tables Overturned
Mark places the action in the final week, immediately on entry to Jerusalem: "And they come to Jerusalem: and he entered into the temple, and began to cast out those who sold and those who bought in the temple, and overthrew the tables of the money-changers, and the seats of those who sold the doves; and he would not allow that any man should carry a vessel through the temple" (Mar 11:15-16). The act is followed by an explanation rooted in Isaiah and Jeremiah: "Is it not written, My house will be called a house of prayer for all the nations? But you⁺ have made it a den of robbers" (Mar 11:17).
The Scourge of Cords
John places a similar scene at a Passover early in the ministry. "And the Passover of the Jews was at hand, and Jesus went up to Jerusalem. And he found in the temple those who sold oxen and sheep and doves, and the changers of money sitting" (Jhn 2:13-14). Here a tool is named: "and he made a scourge of cords, and cast all out of the temple, both the sheep and the oxen; and he poured out the changers' money, and overthrew their tables; and to those who sold the doves he said, Take these things from here; don't make my Father's house a house of merchandise" (Jhn 2:15-16). The disciples' recollection — "Zeal for your house will eat me up" (Jhn 2:17) — frames the act as scriptural fulfillment.
What the Money Changers Were Doing
Both accounts pair the changers with sellers of animals — oxen, sheep, doves. Mark adds those who buy alongside those who sell. The changers' tables and the dove-sellers' seats and the animal-merchants' goods are all swept out together. Across the two passages the temple precinct is being treated as a market, and the action against the money-changers is one part of a single judgment on the trade as a whole — recast in Mark as making the house of prayer "a den of robbers" and in John as making the Father's house "a house of merchandise."