Jesus entered the temple area and drove out all who were buying and selling there. He overturned the tables of the money changers and the benches of those selling doves. Matthew 21:12
“Cleansing the temple (vv. 12–16). Jesus had opened His ministry with a similar act (John 2:13–25). Now, three years later, the temple was defiled again by the “religious business” of the leaders. They had turned the court of the Gentiles into a place where foreign Jews could exchange money and purchase sacrifices.
What had begun as a service and convenience for visitors from other lands soon turned into a lucrative business. The dealers charged exorbitant prices and no one could compete with them or oppose them. Historians tell us that Annas, the former high priest, was the manager of this enterprise, assisted by his sons.
The purpose of the court of the Gentiles in the temple was to give the “outcasts” an opportunity to enter the temple and learn from Israel about the true God. But the presence of this “religious market” turned many sensitive Gentiles away from the witness of Israel. The court of the Gentiles was used for mercenary business, not missionary business.”
Warren Wiersbe in The Bible Exposition Commentary on Mattthew 21:12 (Victor Books: Wheaton, 1989).