Srila Prabhupada: “Some people complain that when they pray to God they do not feel His presence. We should know that this is due to our incapacities, not God’s… The physical conception is temporary, whereas the vibrational conception is eternal. When we enjoy or relish the vibration of Krishna’s teachings in Bhagavad-gita, or when we chant Hare Krishna, 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… Such association with Krishna 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 Krishna 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 Krishna, we will not understand Him, but by listening carefully to His teachings, we can come to the platform of understanding.
We can touch Krishna immediately by sound vibration; therefore we should give more stress to the sound vibration of Krishna and of the spiritual master – then we’ll feel happy and won’t feel separation.”
(“Elevation to Krishna Consciousness” Chapter 4)