Creditors: Often Exacted Debts by Selling the Debtor or Taking Him for a Servant
Source: TTT
Matthew 18:25
Since the man was unable to pay, the master ordered that he be sold to pay his debt, along with his wife and children and everything he owned.
Exodus 21:2
If you buy a Hebrew servant, he is to serve you for six years. But in the seventh year, he shall go free without paying anything.