Silsilat al-Ahadith al-Sahihah

Abdur Rahman bin Abi Laila says: Abu Musa came to visit Sayyiduna Hasan bin Ali (may Allah be pleased with him) during his illness. Sayyiduna Ali (may Allah be pleased with him) asked him: Have you come to visit the sick or to rejoice at the calamity? He replied: To visit the sick. Upon hearing this, Sayyiduna Ali (may Allah be pleased with him) said: If you have truly come to visit the sick, then listen, the Noble Prophet (peace and blessings be upon him) said: "When a person goes to visit his Muslim brother who is sick, he is walking among the chosen fruits of Paradise, and when he sits (by the patient), mercy covers him. If it is in the morning, seventy thousand angels pray for mercy for him until the evening, and if it is in the evening, they pray for him until the morning."