The following is a nice collection of Srila Prabhupada Quotes on the importance of reading and hearing, compiled by Sri Vrindavan das.
Touch Krishna Immediately by Sound Vibration
by Sri Vrindavan das
Lecture 13 January, 1969
Srila Prabhupada: “So although a physical body is not present, the vibration should be accepted as the presence of the Spiritual Master, vibration. What we have heard from the Spiritual Master, that is living.”
Paramahamsa: My question is, a pure devotee, when he comments on Bhagavad-gita, someone who never sees him physically, but he just comes in contact with the commentary, explanation, is this the same thing?
Srila Prabhupada: “Yes, you can associate with Krishna by reading Bhagavad-gita. And these saintly persons, they have given their explanations, comments. So where is the difficulty?”
The Hare Krishna Movement 