Albert Barnes Commentary Numbers 24:22

"Nevertheless Kain shall be wasted, Until Asshur shall carry thee away captive." — Numbers 24:22 (ASV)

Render, For Kain will surely not be destroyed (literally “be for destruction”) until Asshur, etc. The words are not, as they appear in the King James Version, a prediction of evil to the Kenites, but a promise, on the contrary, of safety to be long continued to them (Jeremiah 35:19).