The Prophet ﷺ said, "The sin of two people who exchange insults falls upon the one who started it, unless the wronged party transgresses beyond the limit."Yazid was uncertain whether the wording was "until the wronged party transgresses" or "unless the wronged party transgresses."
حدثنا يزيد بن هارون أخبرنا همام عن قتادة عن يزيد بن عبد الله عن أخيه
عن النبي ﷺ إثم المستبين ما قالا على البادئ حتى يعتدي المظلوم أو إلا أن يعتدي المظلوم شك يزيد
Its isnad is sahih, and it is found in Muslim 4/200, no. 2587, in "Righteousness and Kinship Ties," the prohibition of cursing, and Abu Dawud 4/274, no. 4894, "Manners," those who curse one another, and Tirmidhi 4/352, no. 1981, "Righteousness and Kinship Ties," what has been said about reviling, and Bukhari in Al-Adab 423, and Tabarani in Al-Kabir 17/266, and Ibn Hibban 485, no. 1976, Mawarid, and Bayhaqi 10/135.