Leviticus 25:15

25:15 You may buy it from your fellow citizen according to the number of years since the last jubilee; he may sell it to you according to the years of produce that are left.

Leviticus 25:45

25:45 Also you may buy slaves from the children of the foreigners who reside with you, and from their families that are with you, whom they have fathered in your land, they may become your property.