Merchants under the permission of the high preists. Selling souveniers in the temple to tourists and travelers during the passover.
One can assume the high preist got a cut of proceeds being sold in the temple.
Jesus was pissed that they had turned this holy time of celebration into a commercial enterprise and used a place of worship as a marketing tool and base of operations.
Later, the high preists had him killed for it (among other things). “Who was this peasant that should criticize me? Disrupt my sales and accuse me of hypocracy?”
Yup, and Jesus never said we HAD to take care of every lazy bum that decided to live off other peoples' hard labor. We give a lot to charities, but I refuse to let this idiot in the white hut tell me to give more so he can get more votes.