Al-A'raf · 7:65

65. And I sent to the people of ‘Ād a messenger whose name was Hūd (peace be upon him). Hūd said to them: 'O people! Worship Allah alone, for you have no true God except Him, will you not then be mindful of Him by following His instructions and staying away from what He has prohibited, so that you would be saved from His punishment?'