It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Do not quarrel with your brother, nor joke with him (in a way that causes him harm), and do not make a promise to him which you will break."
Hadith Referenceالادب المفرد / كتاب / 394
Hadith Gradingالألبانی:ضعيف
Hadith Takhrij«ضعيف : أخرجه الترمذي ، كتاب البر و الصلة ، باب ماجاء فى المراء : 1995 - انظر المشكاة : 4892»