Leviticus 25:50
He ... calculate <02803> [reckon.]
cost .... sale <04465 03701> [price of his sale.]
This was a very equitable law, both to the sojourner to whom the man was sold, and to the Israelite who had been sold. The Israelite might redeem himself, or one of his kindred might redeem him; but this must not be done to the prejudice of his master. They were therefore to reckon the years he must have served, from that time till the jubilee; and then taking the current wages of a servant, per year, at that time, multiply the remaining years by that sum, and the aggregate was to be given to his master for his redemption. The Jews hold that the kindred of such a person were bound, if in their power, to redeem him, lest he should be swallowed up among the heathen; and we find (Ne 5:8) that this was done by the Jews on their return from the Babylonish captivity.
rate <03117> [according to the time.]