Al-Adab Al-Mufrad: Disparaging – Hadith No. 425 — The Prophet, may Allah bless him and grant him peace, said, “When two people… (Hadith No. 425)

Abu Hurayra reported that the Prophet, may Allah bless him and
grant him peace, said, "When two people revile each other, the responsibility
for what they say rests on the first to speak as long as the one who wronged
does not become excessive."

Explanation:

Reference: Al-Adab Al-Mufrad, Disparaging, Hadith No. 425