Al-Adab al-Mufrad

It is narrated from Sayyida Umm Darda’ (may Allah be pleased with her), she says that Sayyiduna Abu Darda’ (may Allah be pleased with him) got up at night and prayed, then began to weep and was saying: O Allah, You have made my appearance good, so make my character good as well. He kept making this supplication until morning. I said: O Abu Darda’! You have been supplicating for good character all night. He said: Umm Darda’! If a Muslim servant’s character is good, his character will admit him to Paradise, and if his character is bad, it will admit him to the Fire. And when a Muslim servant is asleep, he is forgiven. I said: O Abu Darda’! How is a sleeping person forgiven? He said: His brother gets up at night and prays Tahajjud, then supplicates to Allah Almighty, and his supplication is accepted, and he supplicates for his brother, so the supplication he makes for his brother is also accepted.