There is great merit in paying a visit to the sick, whether one knows the patient or not. The following is a story of how a man came to take the shahada.
The man was in a hospital sharing a room with a Muslim. One day some people came to visit the Muslim. They came in, hugged the Muslim brother, kissed him, and talked to him with love and affection. They stayed for a while and shared a closeness that was true. After they left, the man asked the Muslim if those were his brothers who had just visited him. The Muslim replied, "No, they learned that I was sick today, at the Friday prayer, and so they came to visit me. I just met them today." This shocked the man. Those people had not acted in an awkward stranger fashion but like true brothers.
This led to the man asking more questions and finally accepting Islam. This duty of visiting the sick was as always blessed by Allah (subhana wa ta’ala). In addition, this time it also served as a vehicle to guide a man to Islam.
This hadith has been sent to me by dailyhadith.