The Mishna (38b) discusses whether a person who has taken a vow not to derive benefit from another can sit or stand in the other person’s presence if the other person is ill and he is fulfilling the mitzva of bikur holim. This leads our Gemara to discuss various aspects of this mitzva.
The baraita teaches that there is no limit to bikur holim. Although Rav Yosef suggests that this means that there is no limit to the reward that a person gets for fulfilling the mitzva of visiting the sick, Abaye counters that this is true of all mitzvot. Rather, Abaye suggests that even a gadol (an adult or a great person) can visit a katan (a child or a lesser person); Rava teaches that it is appropriate for a person to visit his ill friend even 100 times a day. The point of this teaching, according to Abaye, is that even though we find that with regard to some mitzvot (returning lost objects, for example), if performance of the mitzva may cause embarrassment, one is not obligated in the mitzva, this is not the case regarding the mitzva of bikur holim. We never view visiting the sick as belittling the visitor.
Rabbi Aha bar Hanina teaches that a person who visits an ill friend takes with him one-sixtieth of the illness. In response to the question, “In that case shouldn’t we arrange for 60 people to visit every sick person?” Rabbi Aha explains that each subsequent visitor removes only one-sixtieth of what is left, so the illness cannot be eradicated by visitors. Furthermore, this would only be true if the visitor is ben gilo.
The Maharsha suggests that the expression one-sixtieth is a somewhat generic term used in order to indicate “a very small amount,” since in areas of halakha that amount is generally considered to be negligible. With regard to the definition of ben gilo, Rashi suggests that it means someone who is his age, while the Ran says that it is someone who was born under the same constellation. In the Midrash Vayikra Rabba it is presented as someone who “loves him like himself,” which matches the interpretation offered by the Meiri – that it refers to someone whose visit lifts the spirit of the ill person because he is so happy to see him.