It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "The sin of the abuse between two people who revile each other is upon the one who started it, until the oppressed exceeds the limit."
Hadith Referenceالادب المفرد / كتاب السباب / 424
Hadith Gradingالألبانی:حسن صحيح
Hadith Takhrij«حسن صحيح : أخرجه الطبراني فى مسند الشامين : 248 و أبويعلي : 4243 و الخرائطي فى مساوي الاخلاق : 33 و القضاعي فى مسند الشهاب : 329 - انظر الصحيحة : 570»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: ➊ It is forbidden (haram) to abuse a Muslim, which in the hadith has been described as fisq (wickedness) and fujur (immorality), while in another hadith, using abusive language during a quarrel has been declared a sign of hypocrisy. Therefore, one should avoid abusive language as much as possible. ➋ This hadith shows that taking revenge and retaliation is permissible; however, exceeding the limits is impermissible and haram. If someone forgives, then that is a highly virtuous act. ➌ The real criminal is the one who initiates the wrongdoing; however, everyone will receive recompense for their own evil. If someone harasses another to such an extent that the latter resorts to abusive language, then the one who incited the abuse will also be considered a criminal.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 424