The Greek kollubistes (from kollubos, a small coin or exchange fee) refers to the money changers who operated in the Temple precincts. Pilgrims coming to Jerusalem from across the Roman world needed to exchange their foreign coins for the Tyrian shekel — the only currency accepted for the Temple tax. The kollubistai charged a fee for this service and operated in the Court of the Gentiles. Jesus overturned their tables in the Temple cleansing (Matthew 21:12; Mark 11:15).
The Temple cleansing, where Jesus drove out the kollubistai, is one of the most theologically charged actions of His ministry. By commercializing the one court accessible to Gentile worshipers, the money changers had literally occupied the 'house of prayer for all nations' (Isaiah 56:7) with commerce. Jesus quotes both Isaiah 56:7 (the universal mission of the Temple) and Jeremiah 7:11 ('den of robbers') — declaring that economic exploitation has desecrated the space meant for Gentile access to God. The overturned tables signal the coming of a new Temple — the body of Christ — where all nations have direct access.