Numbers 32:39

And the children of Machir the son of Manasseh went to Gilead, and took it, and dispossessed the Amorite which was in it.

The verse stands within Moses' dealing with the two and a half tribes that proposed to remain and settle on the east side of the Jordan, forming part of the account of their settlement there. In this chapter the word destroy when used of people means killing, slaying, or wiping them out, not preserving them alive forever. Moses' solemn admonition that sin would certainly find them out was given because he feared they would depart from God and fail to fulfill their solemn vows. Such unfaithfulness was warned to bring lasting sorrow and final ruin.