'Buy' in the Bible

If you sell anything to your friend or buy from your friend, you shall not wrong one another.

According to the number of years after the Jubilee, you shall buy from your friend. And he is to sell to you according to the number of years of crops [which may be harvested before you must restore the property to him].

As for your male and female slaves whom you may have—you may acquire male and female slaves from the pagan nations that are around you.

Moreover, from the children of the strangers who live as aliens among you, from them you may buy slaves and from their families who are with you, whom they have produced in your land; they may become your possession.