Deuteronomy 33:21

21 And he saw the best for himself because there the portion of the lawgiver was enclosed; and he came at the head of the people; he shall execute the righteousness of the LORD and his judgments with Israel.

Deuteronomy 33:21 Meaning and Commentary

Deuteronomy 33:21

And he provided a first part for himself
That is, the portion of the land of Sihon and Og, as Jarchi rightly interprets it; which was the beginning or firstfruits of the subduing of the land that was promised; this he looked at, chose, and desired it as his inheritance, ( Numbers 32:1 Numbers 32:2 ) ;

because there, [in] a portion of the lawgiver, [was he] seated;
or in the portion and part of the inheritance of Israel was he placed by Moses the lawgiver, according to the will of God; or because there were in it palaces and towers of great personages, lawgivers, kings, and princes, well covered and strongly fortified; or here he was "hid", or "protected", i.e. their families, wives, and children, while they assisted their brethren in subduing Canaan:

and he came with the heads of the people;
either "to" them, to Moses, Eleazar, and the seventy elders, and the heads of the tribes of Israel, to ask leave to have his part and portion on the other side Jordan, or "with" them, as we supply it; came with them over Jordan armed, to assist in the conquest and subduing of the land of Canaan:

he executed the justice of the Lord, and his judgments with Israel;
that is, either he justly and truly fulfilled all his promises and engagements, on condition of which he was placed on the other side; or he, together with the rest of the Israelites, executed the righteous judgment of God upon the Canaanites, in the expulsion and destruction of them.

Deuteronomy 33:21 In-Context

19 They shall call the people unto the mountain; there they shall offer sacrifices of righteousness; therefore they shall suck the abundance of the seas and hidden treasures of the sand.
20 And to Gad he said, Blessed is he that caused Gad to be enlarged; he shall dwell as a lion and shall tear the arm with the crown of the head.
21 And he saw the best for himself because there the portion of the lawgiver was enclosed; and he came at the head of the people; he shall execute the righteousness of the LORD and his judgments with Israel.
22 And to Dan he said, Dan is a lion’s whelp; he shall leap from Bashan.
23 And to Naphtali he said, Naphtali, filled with grace and full of the blessing of the LORD, shall inherit the west and the Negev.
The Jubilee Bible (from the Scriptures of the Reformation), edited by Russell M. Stendal, Copyright © 2000, 2001, 2010