Verse 19. Thou shalt not lend upon usury to thy brother - To an Israelite. They held their estates immediately from God, who while he distinguished them from all other people, might have ordered, had he pleased, that they should have all things in common. But instead of that, and in token of their joint interest in the good land he had given them, he only appointed them, as there was occasion, to lend to one another without interest. This among them would be little or no loss to the lender, because their land was so divided, their estates so settled, and there was so little a merchandise among them, that it was seldom or never they had occasion to borrow any great sums, but only for the subsistence of their family, or some uncommon emergence. But they might lend to a stranger upon usury, who was supposed to live by trade, and therefore got by what he borrowed: in which case 'tis just, the lender should share in the gain. This usury therefore is not oppressive: for they might not oppress a stranger.
Verse 21. Not slack - Not delay: because delays may make them both unable to pay it, and unwilling too.
23. A free-will-offering - Which though thou didst really make, yet being made, thou art no longer free, but obliged to perform it.
Verse 24. At thy pleasure - Which was allowed in those parts, because of the great plenty and fruitfulness of vines there.