Answer:
As Jesus cleansed the temple, He quoted two passages from the Old Testament. The first verse was Isaiah 56:7 which says "My house shall be called a house of prayer for all the people". This indicated to those who heard it that the temple should be a place of prayer and worship and not a place for buying and selling. The second verse He quoted was Jeremiah 7:11 which says "Has this house, which is called by my name, become a den of robbers in your eyes?". This indicated to those who heard it that the temple had become a place of corruption and greed instead of a place of worship and reverence.