Abdullah bin Nafi' said: Sayyiduna Abu Musa al-Ash'ari (may Allah be pleased with him) came to visit Sayyiduna al-Hasan bin Ali (may Allah be pleased with them both), and Sayyiduna Ali (may Allah be pleased with him) said to him: "Have you come to visit the sick, or just as a visitor?" Abu Musa said: "I have come to visit the sick." Sayyiduna Ali (may Allah be pleased with him) said to him: The Messenger of Allah (peace and blessings be upon him) said: "Whoever visits a sick person in the morning, a company of seventy thousand angels seeks forgiveness for him until the evening, and he will have fruit and a garden in Paradise; and if he visits in the evening, a company of seventy thousand angels prays for his forgiveness until the morning, and he will have a garden in Paradise."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6585