Albert Barnes Commentary Joshua 9:21

"And the princes said unto them, Let them live: so they became hewers of wood and drawers of water unto all the congregation, as the princes had spoken unto them." — Joshua 9:21 (ASV)

Render they shall be hewers of wood and drawers of water: menial duties belonging to the lowest classes only (compare the cross-reference). The curse of Noah (Genesis 9:25) on the children of Ham was thus fulfilled to the letter in the case of these Hivites.