Surah Hud, Verse 26

أَن لَّا تَعۡبُدُوٓاْ إِلَّا ٱللَّهَۖ إِنِّيٓ أَخَافُ عَلَيۡكُمۡ عَذَابَ يَوۡمٍ أَلِيمٖ٢٦

an lā taʿbudū illā l-laha innī akhāfu ʿalaykum ʿadhāba yawmin alīmin

That you not worship except Allāh. Indeed, I fear for you the punishment of a painful day."