Ibn Abbas (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him), he (peace and blessings be upon him) said: "Do not quarrel with your (Muslim) brother, nor joke with him in a hurtful manner, nor make a promise to him which you will break." __REF_N__ Tirmidhi, and he said: This hadith is gharib. Its chain is weak. Narrated by Tirmidhi.