No Prophet was sent but that he warned his people against the one-eyed liar. Beware! He is blind in one eye, and your Lord, Glorified and Exalted, is not. Between his eyes, the letters 'k', 'f', and 'r' are written (in Arabic). [Muslim]

"«ما من نبي إلا وقد أنذر أمته الأعور الكذاب، ألا إنه أعور، وإن ربكم - عز وجل - ليس بأعور، مكتوب بين عينيه ك ف ر» [صحيح.] - [متفق عليه.]"