(18) باب النَّهْىِ عَنِ السِّبَابِ،
Abu Huraira reported Allah's Messenger (ﷺ) as saying:
When two persons indulge in hurling (abuses) upon one another, it would be the first one who would be the sinner so long as the oppressed does not transgress the limits.
Reference: Sahih Muslim 2587
In-book reference: Book 45, Hadith 89
USC-MSA web (English) reference(deprecated numbering scheme): Book 32, Hadith 6263