Leviticus 25:51-53

25:51 If there are still many years, in keeping with them he must refund most of the cost of his purchase for his redemption, 25:52 but if only a few years remain until the jubilee, he must calculate for himself in keeping with the remaining years and refund it for his redemption. 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.