To such as keep his covenant,.... The covenant of grace, which is peculiarly the Lord's covenant, as distinct from man's; and which he keeps himself, and is ever mindful of it. This he makes known to his people at conversion; his secret is with them, and he shows them his covenant; the blessings and promises of it; their interest in them, and in himself, as their covenant God: which they "observe" (c), as the word here used signifies; and observing it, they lay hold upon it by faith, as belonging to them; and laying hold upon it, they "keep" it as their own, and keep it fast, and will not part with their interest in it for all the world. And to those that remember his commandments to do them; some read them and hear them, but forget them, at least to do them: these are like a man that beholds his face in a glass, and forgets what manner of man he is; so James compares one that is a forgetful hearer, and not a doer of the word, Jam 1:23. The commandments of God are best remembered, so as to be done, when he puts his laws into the minds of men, and writes them in their hearts, and puts his Spirit within them, to cause them to walk in his statutes, and do them, Jer 31:34. (c) "observantes", Junius & Tremellius; so Piscator, Gejerus.