The Lord - shall keep unto thee the covenant - So we find their continuance in the state of favor was to depend on their faithfulness to the grace of God. If they should rebel, though God had chosen them through his love, yet he would cast them off in his justice. The elect, we see, may become unfaithful, and so become reprobates. So it happened to 24,000 of them, whose carcasses fell in the wilderness because they had sinned; yet these were of the elect that came out of Egypt. Let him that standeth take heed lest he fall.

Wherefore it shall come to pass, if ye hearken to these judgments, and keep and do them,.... Attentively listen to the declaration made of them, and be careful to observe them:

that the Lord thy God shall keep unto thee the covenant and the mercy which he sware unto thy fathers; to bring them into the land of Canaan, and continue them in it; yea, to send the Messiah to them, and bring him the salvation of Israel out of Zion; see Luke 1:68.

The observance of these commandments would also bring great blessings (Deuteronomy 7:12-16). "If ye hearken to these demands of right" (mishpatim) of the covenant Lord upon His covenant people, and keep them and do them, "Jehovah will keep unto thee the covenant and the mercy which He hath sworn to thy fathers." In עקב, for אשׁר עקב (Genesis 22:18), there is involved not only the idea of reciprocity, but everywhere also an allusion to reward or punishment (cf. Deuteronomy 8:20; Numbers 14:24). חסד was the favour displayed in the promises given to the patriarchs on oath (Genesis 22:16).

Wherefore it shall come to pass, if ye hearken to these judgments, and keep, and do them, that the LORD thy God shall keep unto thee the covenant and the {f} mercy which he sware unto thy fathers:

(f) This covenant is grounded in his free grace: therefore in recompensing their obedience, he respects his mercy and not their merits.

7:12 The covenant and the mercy - That is, the covenant of mercy, which he out of his own mere grace made with them.

if: Heb. because

7:12-26 We are in danger of having fellowship with the works of darkness if we take pleasure in fellowship with those who do such works. Whatever brings us into a snare, brings us under a curse. Let us be constant to our duty, and we cannot question the constancy of God's mercy. Diseases are God's servants; they go where he sends them, and do what he bids them. It is therefore good for the health of our bodies, thoroughly to mortify the sin of our souls; which is our rule of duty. Yet sin is never totally destroyed in this world; and it actually prevails in us much more than it would do, if we were watchful and diligent. In all this the Lord acts according to the counsel of his own will; but that counsel being hid from us, forms no excuse for our sloth and negligence, of which it is in no degree the cause. We must not think, that because the deliverance of the church, and the destruction of the enemies of the soul, are not done immediately, therefore they will never be done. God will do his own work in his own method and time; and we may be sure that they are always the best. Thus corruption is driven out of the hearts of believers by little and little. The work of sanctification is carried on gradually; but at length there will be a complete victory. Pride, security, and other sins that are common effects of prosperity, are enemies more dangerous than beasts of the field, and more apt to increase upon us.