Actually it was money changers not lenders. The temple in Jerusalem had its own currency separate from the local and Roman currencies and all purchases around the temple required its use. It was essentially a a mix of extortion and racketeering, where if the people wanted to fallow their religion and fulfil their religious obligations they had to buy sacrifices (sheep, oxen or doves depending) from the temple in temple money which had a horrible exchange rate. Technically the people could bring their own but if they did that it had to be inspected approved to be healthy clean etc, and if it didn't meet standards it could not be used as a sacrifice. However The temple would buy it off at a cut rate as it has obviously inferior...
