Here, 1. Moses summons the assembly. He called all Israel; not only the elders, but, it is likely, as many of the people as could come within hearing, Deu 5:1. The greatest of them were not above God's command, nor the meanest of them below his cognizance; but they were all bound to do. 2. He demands attention: "Hear, O Israel; hear and heed, hear and remember, hear, that you may learn, and keep, and do; else your hearing is to no purpose." When we hear the word of God we must set ourselves to learn it, that we may have it ready to us upon all occasions, and what we have learned we must put in practice, for that is the end of hearing and learning; not to fill our heads with notions, or our mouths with talk, but to rectify and direct our affections and conversations. 3. He refers them to the covenant made with them in Horeb, as that which they must govern themselves by. See the wonderful condescension of divine grace in turning the command into a covenant, that we might be the more strongly bound to obedience by our own consent and the more encouraged in it by the divine promise, both which are supposed in the covenant. The promises and threatenings annexed to some of the precepts, as to the second, third, and fifth, make them amount to a covenant. Observe, (1.) The parties to this covenant. God made it, not with our fathers, not with Abraham, Isaac, and Jacob; to them God gave the covenant of circumcision (Act 7:8), but not that of the ten commandments. The light of divine revelation shone gradually, and the children were made to know more of God's mind than their fathers had done. "The covenant was made with us, or our immediate parents that represented us, before Mount Sinai, and transacted for us." (2.) The publication of this covenant. God himself did, as it were, read the articles to them (Deu 5:4): He talked with you face to face; word to word, so the Chaldee. Not in dark visions, as of old he spoke to the fathers (Job 4:12, Job 4:13), but openly and clearly, and so that all the thousands of Israel might hear and understand. He spoke to them, and then received the answer they returned to him: thus was it transacted face to face. (3.) The mediator of the covenant: Moses stood between God and them, at the foot of the mount (Deu 5:5), and carried messages between them both for the settling of the preliminaries (Ex. 19) and for the changing of the ratifications, Ex. 24. Herein Moses was a type of Christ, who stands between God and man, to show us the word of the Lord, a blessed days-man, that has laid his hand upon us both, so that we may both hear from God and speak to him without trembling.

The Lord our God made a covenant with us in Horeb. Which is Sinai, as Aben Ezra observes; it being the same mountain, only it had two tops, which bore these different names; for certain it is that the decalogue after repeated was given at Sinai, and had the nature and form of a covenant; see Exo 24:7.
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Deuteronomy 5:3

deu 5:3
deu 5:3
deu 5:3The Lord made not this covenant with our fathers,.... That is, not with them only, as Jarchi, Aben Ezra, and Abendana remark; for certain it is that this covenant was made, or law was given, to the immediate fathers of this present generation of Israelites, whose carcasses had fallen in the wilderness; unless this is to be understood of their more remote ancestors, Abraham, Isaac, and Jacob, with whom the covenant of grace was made, or afresh made manifest, especially with the former; when the law, the covenant here spoken of, was not delivered until four hundred and thirty years after, Gal 3:16,

but with us, even us, who are all of us here alive this day; many of them were then present at the giving of the law, and though under twenty years of age, could remember it, and the circumstances of it; and besides, they were the same people to whom it was given, though not consisting wholly of the same individuals.