And to Thamud (We sent) their brother Salih. He said, "O my people! Worship Allah, not for you any god other than Him. Verily has come to you a clear proof from your Lord, This (is) a she-camel (of) Allah for you (as) a Sign. So you leave her (to) eat on (the) earth (of) Allah, and (do) not touch her with harm, lest seizes you a punishment painful."