Riyad as-SalihinChapter 17Hadith 1054
Full Sharh — Riyad as-Salihin 1054
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" ((متفق عليه)). حار رجع.
English Translation
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.".
Source
Riyad as-Salihin(رياض الصالحين)
The Book of the Prohibited actions
Hadith Number
1054