Matthew Poole and continuators on Deuteronomy 15:4

4 Save when there shall be no poor among you : for the LORD shall greatly bless thee in the land which the LORD thy God giveth thee for an inheritance to possess it:

So the words are an exception to the foregoing clause, which they restrain to the poor, and imply that if his brother was rich, he might exact his debt of him, in that year. And indeed this Law seems to be chiefly if not wholly designed and given in favour to the poor and to the borrower, as is manifest from ver. 6, 7, 8, 9, 10, 11. But the words are and may be rendred thus, as in the margent of our Bibles, To the end that there be no poor among you. And so they contain a reason of this Law, to wit, that none be impoverished and ruined by a rigid and unseasonable exaction of debts. They may also be translated thus, Nevertheless of a truth or, assuredly (as the particle chi is oft used) there shall be no poor among you, and the sense may be this, Though I impose this Law upon you, which may seem hard and grievous, yet the truth is, supposing your performance of the conditions of Gods Covenant, you shall not have any great occasion to exercise your charity and kindness in this matter, for God will greatly bless you, &c. so as you shall be in a capacity of lending, and few or none of you will have any need to borrow and thereby to expose his brethren to the inconvenience and burden of this Law. Thus the connexion is plain and easie both with the foregoing and following words. Object. It is said, the poor should never cease, ver. 11. Answ. That also is true and affirmed by God, because he foresaw they would not perform their duty, and therefore would bereave themselves of the promised blessing.

And therefore this will be no great inconvenience nor burden to thee.

Marginal references: Or, to the end that there be no poor among you.