Charles Spurgeon Commentary Deuteronomy 15:4-6

"Howbeit there shall be no poor with thee; (for Jehovah will surely bless thee in the land which Jehovah thy God giveth thee for an inheritance to possess it;) if only thou diligently hearken unto the voice of Jehovah thy God, to observe to do all this commandment which I command thee this day. For Jehovah thy God will bless thee, as he promised thee: and thou shalt lend unto many nations, but thou shalt not borrow; and thou shalt rule over many nations, but they shall not rule over thee." — Deuteronomy 15:4-6 (ASV)

For the LORD shall greatly bless thee in the land which the LORD thy God giveth thee for an inheritance to possess it: only if thou carefully hearken unto the voice of the LORD thy God, to observe to do all these commandments which I command thee this day. For the LORD thy God blesseth thee, as he promised thee:

That little clause, "as he promised thee," is worth noticing. This is the rule of God; he deals with us "according to promise."