In The Old Testament, slavery was voluntary. Slavery was permitted on a voluntary basis, only. It is no longer the law of the land and we cannot practice this form of slavery.
12 If any of your people—Hebrew men or women—sell themselves to you and serve you six years, in the seventh year you must let them go free. 13 And when you release them, do not send them away empty-handed. 14 Supply them liberally from your flock, your threshing floor and your winepress. Give to them as the Lord your God has blessed you. 15 Remember that you were slaves in Egypt and the Lord your God redeemed you. That is why I give you this command today.
16 But if your servant says to you, “I do not want to leave you,” because he loves you and your family and is well off with you, 17 then take an awl and push it through his earlobe into the door, and he will become your servant for life. Do the same for your female servant.
18 Do not consider it a hardship to set your servant free, because their service to you these six years has been worth twice as much as that of a hired hand. And the Lord your God will bless you in everything you do.