Abu Moosa al-Ash’ari visited al-Hasan bin ‘Ali when he was sick. ‘Ali ؓ said to him: Are you visiting him because he is sick, or is this a social visit? Abu Moosa said: Rather I have come to visit him because he is sick. ʿAli ؓ said: I heard the Messenger of Allah ﷺ say: “Whoever visits a sick person in the morning, seventy thousand angels will go out with him, all of them praying for forgiveness for him, until evening comes, and he will have a garden in Paradise. And whoever visits a sick person in the evening, seventy thousand angels will go out with him, all of them praying for forgiveness for him until morning comes, and he will have a garden in Paradise.  

لَهُ عَلِيٌّ أَعَائِدًا جِئْتَ أَمْ زَائِرًا؟ فَقَالَ أَبُو مُوسَى بَلْ جِئْتُ عَائِدًا فَقَالَ عَلِيٌّ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ مَنْ عَادَ مَرِيضًا بَكَرًا شَيَّعَهُ سَبْعُونَ أَلْفَ مَلَكٍ كُلُّهُمْ يَسْتَغْفِرُ لَهُ حَتَّى يُمْسِيَ وَكَانَ لَهُ خَرِيفٌ فِي الْجَنَّةِ وَإِنْ عَادَهُ مَسَاءً شَيَّعَهُ سَبْعُونَ أَلْفَ مَلَكٍ كُلُّهُمْ يَسْتَغْفِرُ لَهُ حَتَّى يُصْبِحَ وَكَانَ لَهُ خَرِيفٌ فِي الْجَنَّةِ  

Abu Moosa al-Ash’ari visited al-Hasan bin ʿAli bin Abi Talib ؓ when he was sick. ʿAli ؓ said to him: Have you come to visit him because he is sick or is it a social visit? He said: No, rather I have come to visit him because he is sick, ‘Ali ؓ said: There is no Muslim who visits a sick person, but seventy thousand angels go out with him, all of them praying for forgiveness for him. If he went out in the morning [they continued to do that] until evening comes, and he will have a garden in Paradise. If he goes out in the evening, seventy thousand angels go out with him, all of them praying for forgiveness for him until morning comes, and he will have a garden in Paradise.”  

لَهُ عَلِيٌّ أَعَائِدًا جِئْتَ أَمْ زَائِرًا؟ قَالَ لَا بَلْ جِئْتُ عَائِدًا قَالَ عَلِيٌّ أَمَا إِنَّهُ مَا مِنْ مُسْلِمٍ يَعُودُ مَرِيضًا إِلا خَرَجَ مَعَهُ سَبْعُونَ أَلْفَ مَلَكٍ كُلُّهُمْ يَسْتَغْفِرُ لَهُ إِنْ كَانَ مُصْبِحًا حَتَّى يُمْسِيَ وَكَانَ لَهُ خَرِيفٌ فِي الْجَنَّةِ وَإِنْ كَانَ مُمْسِيًا خَرَجَ مَعَهُ سَبْعُونَ أَلْفَ مَلَكٍ كُلُّهُمْ يَسْتَغْفِرُ لَهُ حَتَّى يُصْبِحَ وَكَانَ لَهُ خَرِيفٌ فِي الْجَنَّةِ  

[Machine] The Messenger of Allah, peace be upon him, said: "Whenever a person visits a sick person in the evening, seventy thousand angels go out with him and seek forgiveness for him until morning. He will also have a garden (i.e., a reward) in Paradise. And whoever visits a sick person in the morning, seventy thousand angels go out with him and seek forgiveness for him until evening. He will also have a garden (i.e., a reward) in Paradise." This hadith has a valid chain of narrators according to the conditions set by the two sheikhs (i.e., Bukhari and Muslim), but they did not include it in their collections as a group of narrators did not include it due to the statement of Al-Hakam bin 'Utaybah and Mansur bin Al-Mu'tamir and their narrations from Ibn Abi Layla from Ali. However, I believe in the authenticity of the additional narrator.  

قَالَ رَسُولُ اللَّهِ ﷺ «مَا مِنْ رَجُلٍ يَعُودُ مَرِيضًا مُمْسِيًا إِلَّا خَرَجَ مَعَهُ سَبْعُونَ أَلْفَ مَلَكٍ يَسْتَغْفِرُونَ لَهُ حَتَّى يُصْبِحَ وَكَانَ لَهُ خَرِيفٌ فِي الْجَنَّةِ وَمَنْ أَتَاهُ مُصْبِحًا خَرَجَ مَعَهُ سَبْعُونَ أَلْفَ مَلَكٍ يَسْتَغْفِرُونَ لَهُ حَتَّى يُمْسِيَ وَكَانَ لَهُ خَرِيفٌ فِي الْجَنَّةِ» هَذَا إِسْنَادٌ صَحِيحٌ عَلَى شَرْطِ الشَّيْخَيْنِ وَلَمْ يُخَرِّجَاهُ لِأَنَّ جَمَاعَةً مِنَ الرُّوَاةِ أَوْقَفُوهُ عَنِ الْحَكَمِ بْنِ عُتَيْبَةَ وَمَنْصُورِ بْنِ الْمُعْتَمِرِ عَنِ ابْنِ أَبِي لَيْلَى عَنْ عَلِيٍّ مِنْ حَدِيثِ شُعْبَةَ عَنْهُمَا وَأَنَا عَلَى أَصْلِي فِي الْحُكْمِ لِرَاوِي الزِّيَادَةِ  

"مَا مِنْ رَجُلٍ يَعُودُ رَجُلًا مُمْسِيًا إِلا خَرَجَ مَعَهُ سَبْعُون ألفَ مَلَكٍ يَسْتَغْفِرُونَ لَهُ حتى يُصْبِحَ، وَمَنْ أَتَاه مُصْبِحًا، خَرَجَ مَعَه سَبْعُونَ أَلفَ مَلكٍ يَسْتَغْفِرُونَ لَهُ حَتَّى يُمْسِى".  

"عَنْ الْحَكَمِ بْنِ عَبْدِ الله بْنِ نَافِعٍ قَالَ: عَادَ أَبُو مُوسَى الْحَسَنَ بْنَ عَلِىٍّ، فَقَالَ عَلِىٌّ: أَمَا إِنَّهُ، مَا مِنْ مُسْلِمٍ يَعُودُ مَرِيضًا إِلَّا خَرَجَ مَعَهُ سَبْعُونَ أَلْفَ مَلَكٍ يَسْتَغْفِرُونَ لَهُ إِنْ كَانَ مُصْبِحًا حَتَّى يُمْسِىَ، وَكَانَ لَهُ خَرِيفٌ فِي الْجنَّةِ وَإِنْ كان مُمْسِيًا خَرَجَ مَعَه سَبْعُونَ أَلْفَ مَلَكٍ كُلُّهُمْ يَسْتَغْفِرُونَ لَهُ وَكَانَ لَهُ خَرِيفٌ فِي الْجَنَّةِ".