(Srila Prabhupada and his beloved books—click to enlarge)
"There are two conceptions of presence—the physical conception and the vibrational conception. The physical conception is temporary, whereas the vibrational conception is eternal. When we enjoy or relish the vibration of Kṛṣṇa’s teachings in Bhagavad-gītā, or when we chant Hare Kṛṣṇa, we should know that by those vibrations He is immediately present. He is absolute, and because of this His vibration is just as important as His physical presence. When we feel separation from Kṛṣṇa or the spiritual master, we should just try to remember their words of instructions, and we will no longer feel that separation. Such association with Kṛṣṇa and the spiritual master should be association by vibration, not physical presence. That is real association. We put so much stress on seeing, but when Kṛṣṇa was present on this earth, so many people saw Him and did not realize that He is God; so what is the advantage of seeing? By seeing Kṛṣṇa, we will not understand Him, but by listening carefully to His teachings, we can come to the platform of understanding. We can touch Kṛṣṇa immediately by sound vibration; therefore we should give more stress to the sound vibration of Kṛṣṇa and of the spiritual master—then we’ll feel happy and won’t feel separation."