Abu Moosa al-Ash`ari visited al-Hasan bin `Ali (when he was sick). `Ali (رضي الله عنه) came in and said: Have you come to visit him (because he is sick), O Abu Moosa, or is it just a (social) visit? He said: No. O Ameer al-Mu`mineen; rather I have come to visit him (because he is sick), ‘Ali (رضي الله عنه) said: I heard the Messenger of Allah (ﷺ) say: `No Muslim visits his fellow Muslim when he is sick but seventy thousand angels send blessings upon him from morning until evening, and Allah grants him a stream in Paradise.` said: O Ameer al-Mu`mineen, what is a stream? He said: The channel that waters palm trees.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبِيدَةُ بْنُ حُمَيْدٍ، حَدَّثَنِي ثُوَيْرُ بْنُ أَبِي فَاخِتَةَ، عَنْ أَبِيهِ، قَالَ عَادَ أَبُو مُوسَى الْأَشْعَرِيُّ الْحَسَنَ بْنَ عَلِيٍّ قَالَ فَدَخَلَ عَلِيٌّ رَضِيَ اللَّهُ عَنْهُ فَقَالَ أَعَائِدًا جِئْتَ يَا أَبَا مُوسَى أَمْ زَائِرًا فَقَالَ يَا أَمِيرَ الْمُؤْمِنِينَ لَا بَلْ عَائِدًا فَقَالَ عَلِيٌّ رَضِيَ اللَّهُ عَنْهُ فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ مَا عَادَ مُسْلِمٌ مُسْلِمًا إِلَّا صَلَّى عَلَيْهِ سَبْعُونَ أَلْفَ مَلَكٍ مِنْ حِينَ يُصْبِحُ إِلَى أَنْ يُمْسِيَ وَجَعَلَ اللَّهُ تَعَالَى لَهُ خَرِيفًا فِي الْجَنَّةِ قَالَ فَقُلْنَا يَا أَمِيرَ الْمُؤْمِنِينَ وَمَا الْخَرِيفُ قَالَ السَّاقِيَةُ الَّتِي تَسْقِي النَّخْلَ.
sunnah.com