Deuteronomy 33:4

Moses commanded us a law,.... The law was of God, it came forth from his right hand, Deuteronomy 33:2; it is of his enacting, a declaration of his will, and has his authority stamped upon it, who is the lawgiver, and which lays under obligation to regard it; but it was delivered to Moses, and by him to the children of Israel, on whom he urged obedience to it; and so it is said to come by him, and sometimes is called the law of Moses, see John 1:17;

[even] the inheritance of the congregation of Jacob; which either describes the persons who were commanded to keep the law, the tribes of Jacob or congregation of Israel, who were the Lord's people, portion, and inheritance, Deuteronomy 32:9; or the law commanded, which was to be valued, not only as a peculiar treasure, but to be considered a possession, an estate, an inheritance, to be continued among them, and to be transmitted to their posterity, see Psalms 119:111; these are the words of the people of Israel, and therefore are thus prefaced in the Targums of Jonathan and Jerusalem,

"the children of Israel said, Moses commanded, c.''

they were represented by Moses.