The conflict between Jesus and the moneychangers in the Jerusalem Temple is one of the very few events in Jesus' life which is described by all four gospels. The event is sometimes euphemistically referred to as the Cleansing of the Temple, though that phrase is misleading for various reasons and I prefer to avoid it.
The Setting
Herod the Great put a great deal of work into the Jerusalem Temple during his reign, and spent many years adding plazas, porticoes, and monuments to the complex. Many of these building projects continued after Herod's death in 4 BCE, and some were still incomplete even when Jesus reached adulthood thirty-odd years later.
The Temple in Jesus' time consisted of numerous "courts" that were open to different groups of people for the purpose of sightseeing, socializing, and, of course, taking part in rituals. Gentiles were allowed to visit the outer plaza and mill about, just as non-Christian tourists are invited to tour cathedrals today. Pagans were warned away from entering the areas restricted to Jews by means of inscriptions engraved on a low balustrade called the soreg. Further in, past the soreg, there was a court where all Jewish people were permitted to meet, then a smaller court restricted to Jewish men, then a still smaller court restricted to priests, then finally the sanctuary itself where the ark of the Covenant was kept.
Sacrifices took place regularly, and Jewish people from around the known world were encouraged to bring their sin offerings whenever they could. However, the Temple was busiest during major festivals: thousands and thousands of pilgrims and tourists would flock to Jerusalem on the holiest days of the Jewish year. It was during one of these, Passover, when the "Cleansing" was supposed to have taken place.
Keep in mind that the entire Temple complex measured about a square kilometer, give or take. If you're imagining Jesus starting an argument in a building the size of a modern church, you haven't got your sense of proportion right; it's more like an argument taking place in front of a food stand in an amusement park. This fact has led Paula Fredriksen to wonder how much of an impact the conflict could actually have had: how many people would have noticed one angry man in all the noise and bustle? how much could it really have inconvenienced the hundreds of priests, merchants, and "support staff" who worked there?
The Conflict
John disagrees with the other three Gospels on the timing of what we in religious studies like to call the Temple tantrum. John places the event at the beginning of Jesus' ministry, describing it in the second chapter of his gospel.
The Passover of the Jews was near, and Jesus went up to Jerusalem. In the temple he found those who were selling cattle, sheep, and doves, and the money changers seated at their tables. Making a whip of cords, he drove all of them out of the temple, both the sheep and the cattle. He also poured out the coins of the money changers and overturned their tables. He told those who were selling the doves, "Take these things out of here! Stop making my Father's house a marketplace!"
The Synoptic authors, by contrast, place this event at the end of Jesus' ministry; in fact, they make it clear that it was this action of Jesus that caused the Roman and Jewish authorities to decide to kill him. (For John, it was the raising of Lazarus that got Jesus sentenced to death.)
Here is Mark's version:
Then they came to Jerusalem. And he entered the temple and began to drive out those who were selling and those who were buying in the temple, and he overturned the tables of the money changers and the seats of those who sold doves; and he would not allow anyone to carry anything through the temple. He was teaching and saying, "Is it not written, 'My House shall be called a house of prayer for all the nations'? But you have made it a den of robbers."
Matthew and Luke both tell an abbreviated version of the story (see Matthew 21:12-13 and Luke 19:45-48).
What was going on in there?
This story has been interpreted in a myriad of ways. For some, it is a blanket condemnation of capitalism. For others, it serves as a judgement on animal sacrifice. For still others, it condemns the Jewish priestly hierarchy (and for some Protestants, it leads to a profound mistrust of all priesthoods and all hierarchies).
For many, including the evangelists themselves, this event demonstrated that Jesus fulfilled a number of prophecies in the Old Testament. For example, Malachi 3:1-2 describes how "the Lord whom you seek will suddenly come to his temple." Zechariah 14:21 imagines a perfect day when merchants and pagans will no longer be present in the Temple. Jeremiah 7 portrays God bitterly complaining about the people who steal and abuse from others then seek out sanctuary in the Temple (the "den of thieves" phrase is a direct and deliberate quotation of the Jeremiah passage).
Furthermore, the conflict in the Temple is itself seen as a prophecy. John explains that the Temple would soon be destroyed (it was, in the Jewish Wars of 68-72 CE, and has not been rebuilt since), and compares it to Jesus' body which would also be destroyed and rebuilt.
As a pinko socialist and longtime vegetarian, I have a great deal of sympathy for the readers who use this story to justify their position on the relationship between money, slaughter, and spirituality. However, if I may act as devil's advocate just for a moment, allow me to remind you that there were good religious reasons for the moneychangers to work on Temple grounds. People travelled from all over the continent to take part in the festivals, and local cash, then as now, is not good everywhere. Is it so wrong to seek out a Jewish moneychanger rather than a Roman one? Similarly, if you're a good Jew wishing to fulfil God's law, is it such a bad thing to buy your doves when you arrive at the temple rather than carting them all the way across town? The answers to these questions are not as simple as the evangelists would have you believe.
There is a popular theory that the moneychangers were not only exchanging foreign currency for local, but that they were also making sure everyone had coins that did not contain portraits of pagan gods on them, so that nobody would be breaking the first commandment within the Temple precincts. However, the Tyrian shekel, used for Temple commerce, did have an image of the god Melkart. Later the Talmud would judge that the payment of temple dues was important enough to make the use of this coin acceptable, even in the Temple. Perhaps there were some Zealot-affiliated Jews (might Jesus have been among them?) who considered this compromise unacceptable.
At any rate, it's clear that Jesus had a radical vision for the Jerusalem Temple, and his anger at the moneychangers made a profound impact on his followers.
Notes:
All Biblical citations are drawn from the NRSV.
To see some pictures of ancient shekels, along with a very amusing Doré engraving of Jesus driving out the moneychangers, see this web site.
An artist's reconstruction of Herod's temple complex can be found here.