Tafsir of Hud 11:26

أن ﻻ تعبدوا إﻻ الله

That you worship none but Allah; This can also be seen in his statement,

إني أخاف عليكم عذاب يوم أليم

surely, I fear for you the torment of a painful Day. This means, "If you all continue doing this, then Allah will punish you with a severe punishment in the Hereafter.'' Then Allah says,