Abu Dharr (May Allah be pleased with him) said:
I heard the Messenger of Allah ﷺ 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."

[Al-Bukhari and Muslim].

وعن أبي ذر رضي الله عنه أنه سمع رسول الله ﷺ يقول:
"من دعا رجلا بالكفر، أو قال: عدو الله، وليس كذلك إلا حار عليه" ((متفق عليه)).
حار رجع.