Charles Ellicott Commentary Numbers 21:25

"And Israel took all these cities: and Israel dwelt in all the cities of the Amorites, in Heshbon, and in all the towns thereof." — Numbers 21:25 (ASV)

And Israel dwelt in all the cities of the Amorites. —If, as appears most probable, this and the thirty-first verse form a part of the original narrative, the word translated dwelt should be interpreted as sojourned or stayed, and understood, in accordance with the word's frequent use (for example, in Numbers 22:5 and Numbers 22:8), to mean a temporary occupation or encampment. The permanent occupation of the eastern side of the Jordan by the Israelites was after the death of Moses.