John Gill Commentary Deuteronomy 33:4

"Moses commanded us a law, An inheritance for the assembly of Jacob." — Deuteronomy 33:4 (ASV)

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) (John 7:19John 7:23) (8:5) ;

[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'' they were represented by Moses.