1 Samuel 8:10-12

10Now Samuel reported all the words of Adonai to the people who were asking him for a king.

11“This will be the practice of the king that will reign over you,” he said. “He will draft your sons and assign them as his charioteers and horsemen, and they will run before his chariots.

12He will appoint them as commanders of thousands and captains of fifties, also some to plow his fields, reap his harvest, make his weapons of war and the equipment for his chariots.