Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) narrates: Whenever we saw a man cursing his brother, we considered that he had committed a major sin.
Al-Tabarani recorded it in al-Mu'jam al-Awsat, and something similar in al-Mu'jam al-Kabir. The chain of al-Mu'jam al-Awsat is jayyid (good), and the chain of al-Mu'jam al-Kabir contains Ibn Lahi'ah, who is weak.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدب / 13009
Hadith Gradingمحدثین:إسنادِ اوسط جید، جبکہ إسنادِ کبیر بوجہ ابن لہیعہ ضعیف