Persons whose profession was to sell or exchange Roman or other moneys for Jewish money acceptable in the temple worship. In NT times regions and cities issued their own money. This caused Jews of the Dispersion, those who lived outside of Judea, to bring many kinds of money to Jerusalem. To help visitors change money into that acceptable in Jerusalem, money changers set up tables in the temple court of the Gentiles. Syrian silver coins were the money of Jerusalem then, and worshipers used them to pay their temple tax of a half shekel and to buy sacrifices for the altar.
Three words are translated “money changers”: kollubistes (Matt 21:12; Mark 11:15; John 2:15) of Semitic origin referred to the exchange rate or commission; Kermatistes (John 2:14) referred to a dealer in small change; and trapetzites (Matt 25:27), which Luke used in a slightly different form (trapezan, 19:23, or shulhanim in Hebrew), referred to a money agent who sat at a table.
Money changers were in the area with vendors who sold animals, birds, and other items used in temple worship and sacrifices. Such transactions were numerous and required the service of brokers who knew the value of foreign money. Some exchangers profited greatly and loaned their money along with what others invested with them. Their interest rates ranged from 20 to 300 percent per years.
In anger at this corruption of the purpose of the temple, Jesus turned over the tables of the money changers and drove them and the sellers of animals out of the temple court (Matt 21:12).