Tafsir of Ash-Shu`ara' 26:154

"You are nothing but a human being like us." According to the first interpretation, this is an emphasis of the previous statement; according to the second, it is a new statement serving as a justification—meaning: you are bewitched because you are a human like us, possessing no distinction over us, and your claim is merely a result of a flaw in your intellect. "Then bring [a sign]" as proof of the veracity of your claim, "if you are of the truthful."