Midrash su Salmi 49:10

When Rabbi and R. Chiya who were once on the road came to a city, they asked: "Is there a scholar here? We would like to pay him a visit." They were told that there was a scholar there, but that he was blind. Said R. Chiya to Rabbi: "You, as a Nasi, remain here, so as not to lower your dignity, and I will go to see him." Rabbi, however, insisted and went with him. When they were departing, the blind man said to them: "You have come to see a countenance that can be seen, but cannot see; therefore [my wish is that] ye deserve to see that countenance which sees all, but cannot be seen." Rabbi then said [to R. Chiya]: "Had I listened to you, [not to visit him] I would not have received this blessing." They then asked the blind man: "From whom have you heard this?" [that to visit a scholar is so great a merit]. "I heard it at the lecture of R. Jacob of the village of Hitaya, who used to visit his master daily. When he became old, his master said to him: 'Do not take this trouble now, for you are too old to walk every day.' He answered: 'Do you hold the following passage in such light esteem? (Ps. 49, 10) Should he still live forever, and not see the pit? This means: Why should he not see the pit? Because he saw the wise men while dead. Now, if one who sees the wise while dead, lives forever, how much more so should he who comes to see them while alive.'"