נכה nkh "strike" in the hiphil, the only form to appear in Amos, means "strike, strike a blow, hit" or even "destroy". In Amos always Adonai is the one "striking". Once he "strikes" Israelite crops with disease 4:9 and three times he "strikes" buildings 3:15; 6:11; 9:1 (or in this last case orders it "struck"). Where buildings are involved translators have sometimes chosen the notion "destroy" - I have preferred to keep alive the picture of Adonai's personal involvement in the destruction, which Amos seems to intend.