Riyad as-Salihin, Book 18, Hadith 1561 (In-Book) ⓘ
Abu Hurairah (May Allah be pleased with him) said: The Messenger of Allah said, "When two persons indulge in abusing each other, the beginner will be the sinner so long as the oppressed does not transgress the limits."[Muslim].
وعن أبي هريرة رضي الله عنه أن رسول الله صلى الله عليه وسلم قال: "المتسابان ما قالا فعلى البادي منهما حتى يعتدي المظلوم" ((رواه مسلم)).