Charles Ellicott Commentary Numbers 33:56

"And it shall come to pass, that, as I thought to do unto them, so will I do unto you." — Numbers 33:56 (ASV)

Moreover it shall come to pass ... — Better, And it shall come to pass that, as I have thought (or, determined) to do to them, so will I do to you. It must be borne in mind that the idolatrous inhabitants of Canaan were never wholly exterminated, and the pernicious influence they exercised was felt throughout the entire history of the Israelites until the judgments threatened against them were finally executed in the Assyrian and Babylonian captivities.