‘ Howbeit there shall be no poor with you, (for Yahweh will surely bless you in the land which Yahweh your God is giving to you for an inheritance to possess it), if only you diligently listen to the voice of Yahweh your God, to observe to do all this commandment which I command you this day.'
A further reason for the release is that the need for it would only arise if Israel had been disobedient to Yahweh. For if they listened diligently to His voice, to observe all the commandments given by Moses, there would be no poor, and therefore no borrowers, among them, for Yahweh would then bless the land, which He had given them as an inheritance that they could possess, to such an extent that poverty would be ruled out. Thus the fact that there was a debtor would indicate Israel's failure, and release of the debtor would be a kind of partial atonement for that failure.
However, the chiasmus clearly brings out that the reason that there will be no poor will be because of God's blessing of the land so that the third year tithe will be of such munificence that there will be sufficient for all, and none will be poor. But this will only be so if they are faithful to the covenant so that God blesses the land.