أَوَلَم يَتَفَكَّروا ۗ ما بِصاحِبِهِم مِن جِنَّةٍ ۚ إِن هُوَ إِلّا نَذيرٌ مُبينٌ

Then do they not give thought? There is in their companion [Muhammad] no madness. He is not but a clear warner.