Moses
Leviticus 25:50ESV·traditional attribution

He shall calculate with his buyer from the year when he sold himself to him until the year of jubilee, and the price of his sale shall vary with the number of years. The time he was with his owner shall be rated as the time of a hired worker.

Matthew Henry Presbyterian @wholebiblehenry

We have here the laws concerning servitude, designed to preserve the honour of the Jewish nation as a free people, and rescued by a divine power out of the house of bondage, into the glorious liberty of God's sons, his first-born. Now the law is, I. That a native Israelite should never be made a bondman for perpetuity.

Commenting on Leviticus 25:39-55

John Gill Reformed Baptist @doctorgill

And he shall reckon with him that bought him,.... That is, either the man himself should reckon with him, or whoever undertook to redeem him: from the year that he was sold to him unto the year of jubilee; and so count how many years he had served, and how many were yet to come; and by this it appears, that one thus sold was...

Geneva Bible Notes Reformed @genevanotes

And he shall reckon with him that bought him from the year that he was sold to him unto the year of jubile: and the price of his sale shall be according unto the number of years, according to the time of an hired servant shall it be with him. (x) Which remains yet to the Jubile.