'Purchaser' in the Bible

Then he [or his redeemer] shall calculate with his purchaser from the year when he sold himself to the purchaser to the Year of Jubilee, and the [original] price of his sale shall be adjusted according to the number of years. The time he was with his owner shall be considered as that of a hired man.

If there are still many years [before the Year of Jubilee], in proportion to them he must refund [to the purchaser] part of the price of his sale for his redemption and release.