Yahya related to me from Malik that he had heard from Amir ibnSad ibn Abi Waqqas that his father said, "There were two brothers, oneof whom died forty nights before the other. The merit of the first wasbeing mentioned in the presence of the Messenger of Allah, may Allahbless him and grant him peace, and he said, 'Wasn't the other one amuslim?' They said, 'Of course, Messenger of Allah, and there was noharm in him.' The Messenger of Allah, may Allah bless him and granthim peace, said, 'What will make you realise what his prayer hasbrought him. The prayer is like a deep river of sweet water running byyour door into which you plunge five times a day. How much of yourdirtiness do you think that will leave? You do not realise what hisprayer has brought him.' "
USC-MSA web (English) reference: Book 9, Hadith 94
Arabic reference: Book 9, Hadith 426