Deuteronomy 15:13

13.And when thou sendest him out free from thee. Here not only is the enfranchisement of slaves enjoined, but an exhortation to liberality is also added, viz., that they should not send away their slaves without their hire; for this is not a civil enactment for the purpose of extorting from the avaricious more than they were willing to give. The rule of Paul here applies:

“Every man according as he purposeth in his heart, so let him give; not grudgingly or of necessity: for God loveth a cheerful giver.” (2 Corinthians 9:7.)

But, since the Hebrew slaves were brethren, God would not allow them to be placed in a worse condition than hirelings. That He commands them to be furnished out of the wine-press, and floor, and flock, does not mean that they were to be enriched, or that a large provision should be assigned to them, but He justly lays a constraint on the rich, whose varied abundance supplied them with the means of liberality; as if He would show them from whence they received their gratuitous gifts, which were at the same time a just compensation for the labors of their slaves.