John Calvin Commentary Numbers 32:2

"the children of Gad and the children of Reuben came and spake unto Moses, and to Eleazar the priest, and unto the princes of the congregation, saying," — Numbers 32:2 (ASV)

The children of Gad and the children of Reuben came. Their request was apparently a reasonable one, that since God had driven out the inhabitants of the land, and its fertility invited them to dwell there, the possession of these empty and deserted fields should not be denied them. Their modesty also was praiseworthy, in that they neither detached themselves from the people, nor seditiously and violently seized the places so suitable for them; rather, they sought to obtain them by the permission of Moses and the elders, as if they submitted their cause to their decision.

But as I have just said, their private interest had so taken hold of their minds that the main point did not occur to them: namely, that the land of Canaan was set before them all so that they might dwell together there, separate from heathen nations; and again, that it was unjust for them not only to enjoy rest while the others were fighting, but also to be settled in a secure and peaceful habitation, while the ten tribes were still advancing to the conquest of the promised land.