Leviticus 25:43

25:43 You must not rule over him harshly, but you must fear your God.

Leviticus 25:46

25:46 You may give them as inheritance to your children after you to possess as property. You may enslave them perpetually. However, as for your brothers the Israelites, no man may rule over his brother harshly.

Leviticus 25:53

25:53 He must be with the one who bought him like a yearly hired worker. The one who bought him must not rule over him harshly in your sight.