Mosiah 21:3

Now they durst not slay them, because of the oath which their king had made unto Limhi; but they would smite them on their cheeks, and exercise authority over them; and began to put heavy burdens upon their backs, and drive them as they would a dumb ass:

They didn’t dare kill them because of the promise their king had made to Limhi. But they would hit them on their faces and boss them around. They began to put heavy loads on their backs. They made them work like animals.

They couldn’t kill them—their king had made an oath to Limhi—but they slapped them across the face, bossed them around, loaded them down with heavy burdens, and drove them like pack animals.