Good mannerisms is not only something that will aid in one’s chances to enter into the paradise. It is as well as sign to the completeness of one’s level of emaan (belief). Before discussing the issue, I want to remind you of the statement of the Prophet (may Allah’s peace and blessings be upon him) when he stated, “Verily from the most complete believer in terms of their emaan (belief), is the best of them in their mannerisms” [Reported by Imaam at Tirmadhi]. This particular hadeeth was reported as authentic by Sheikh al Albaani.
