Charles Ellicott Commentary Numbers 32:1

"Now the children of Reuben and the children of Gad had a very great multitude of cattle: and when they saw the land of Jazer, and the land of Gilead, that, behold, the place was a place for cattle;" — Numbers 32:1 (ASV)

Now the children of Reuben and the children of Gad ... — These tribes had occupied a contiguous position in their encampments for thirty-eight years (Numbers 2:10; Numbers 2:14), and it was natural that they should desire to be permanently located near each other.

The land of Jazer. — See Numbers 21:32. This district was remarkable for its rich pasture-land.

The land of Gilead. — This land lay north and south of the Jabbok, and even in its present desolation shows traces of its great fertility.