وعن أبي ذر رضي الله عنه أنه سمع
رسول الله صلى الله عليه وسلم يقول: «من دعا رجلا بالكفر، أو قال: عدو الله، وليس كذلك إلا حار عليه»
I heard the Messenger of Allah (sallallahu alayhi wa sallam) saying, “If somebody accuses another of disbelief or calls him the enemy of Allah, such an accusation will revert to him (the accuser) if the accused is innocent.”.
Riyad as-Salihin 1733, Book 18, The Book of the Prohibited actions, Hadith 223. 1 min read