John Gill Commentary 2 Kings 21:8

"neither will I cause the feet of Israel to wander any more out of the land which I gave their fathers, if only they will observe to do according to all that I have commanded them, and according to all the law that my servant Moses commanded them." — 2 Kings 21:8 (ASV)

Neither will I make the feet of Israel move any more out of
the land which I gave their fathers
Or suffer them to be carried captive into another land, as in the times of the judges; that is, on the following condition:

only if they will observe to do according to all the law that my
servant Moses commanded them
by obedience to which they had the tenure of the land of Canaan, (Isaiah 1:19) .