The Messenger of Allah ﷺ said, "Every prophet warned his people about the one-eyed liar. He is one-eyed, but your Lord is not one-eyed. Written between his eyes are the letters K-F-R."
قال رسول الله ﷺ ما من نبي إلا وقد أنذر أمته الأعور الكذاب، ألا إنه أعور، وإن ربكم ليس بأعور ومكتوب بين عينيه ك ف ر.
Bukhari related it in "The Book of Tribulations" (7131), and Muslim in "The Book of Tribulations" (2933), both through the route of Shubah, from Qatada, who said, I heard Anas bin Malik say, then he mentioned it.