Muwatta Malik, Book 9, Hadith 94 (USC-MSA) ⓘ

Yahya related to me from Malik that he had heard from Amir ibn Sad ibn Abi Waqqas that his father said, "There were two brothers, one of whom died forty nights before the other. The merit of the first was being mentioned in the presence of the Messenger of Allah, may Allah bless him and grant him peace, and he said, 'Wasn't the other one a muslim?' They said, 'Of course, Messenger of Allah, and there was no harm in him.' The Messenger of Allah, may Allah bless him and grant him peace, said, 'What will make you realise what his prayer has brought him. The prayer is like a deep river of sweet water running by your door into which you plunge five times a day. How much of your dirtiness do you think that will leave? You do not realise what his prayer has brought him.' "

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ عَنْ عَامِرِ بْنِ سَعْدِ بْنِ أَبِي وَقَّاصٍ، عَنْ أَبِيهِ، أَنَّهُ قَالَ كَانَ رَجُلاَنِ أَخَوَانِ فَهَلَكَ أَحَدُهُمَا قَبْلَ صَاحِبِهِ بِأَرْبَعِينَ لَيْلَةً فَذُكِرَتْ فَضِيلَةُ الأَوَّلِ عِنْدَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ أَلَمْ يَكُنِ الآخَرُ مُسْلِمًا ‏"‏ ‏.‏ قَالُوا بَلَى يَا رَسُولَ اللَّهِ وَكَانَ لاَ بَأْسَ بِهِ ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ وَمَا يُدْرِيكُمْ مَا بَلَغَتْ بِهِ صَلاَتُهُ إِنَّمَا مَثَلُ الصَّلاَةِ كَمَثَلِ نَهْرٍ غَمْرٍ عَذْبٍ بِبَابِ أَحَدِكُمْ يَقْتَحِمُ فِيهِ كُلَّ يَوْمٍ خَمْسَ مَرَّاتٍ فَمَا تَرَوْنَ ذَلِكَ يُبْقِي مِنْ دَرَنِهِ فَإِنَّكُمْ لاَ تَدْرُونَ مَا بَلَغَتْ بِهِ صَلاَتُهُ ‏"‏ ‏.‏