He provided the first part - That is, he chose for himself a very excellent portion, viz., the land of Sihon and Og, in which this tribe had requested to be settled by the lawgiver, viz., Moses, from whom they requested this portion, Numbers 32:1-5.
He came with the heads of the people - Notwithstanding this portion fell unto them on the east side of Jordan, yet they proceeded with the heads of the people, the chiefs of the other tribes.
To execute the justice of the Lord - To extirpate the old inhabitants of the country, according to the decree and purpose of the Lord. See on Numbers 32 (note).
The first fruits of the conquest made by Israel were assigned to Gad and Reuben by Moses, at their own request.
Because seated - Render, because there was the leader‘s portion reserved, i. e., there was reserved the fitting portion for Gad as a leader in war.
And he came - i. e., he joined the other leaders to fulfill the commands of God respecting the conquest of Canaan (compare Numbers 32:17, Numbers 32:21, Numbers 32:32; Joshua 1:14). Moses regards the promise of the Gadites to do this as already redeemed.