His existence can be realized by one who has the single qualification of submissiveness and who thereby becomes a surrendered soul. The development of submissiveness is the cause of proportionate spiritual realization, by which one can ultimately meet the Supreme Lord in person, as a man meets another man face to face.

Because of his development of transcendental attachment for the Supreme Lord, a surrendered soul feels the presence of his beloved everywhere, and all his senses are engaged in the loving service of the Lord. His eyes are engaged in seeing the beautiful couple Sri Radha and Krsna sitting on a decorated throne beneath a desire tree in the transcendental land of Vrndavana. His nose is engaged in smelling the spiritual aroma of the lotus feet of the Lord. Similarly, his ears are engaged in hearing messages from Vaikuntha, and his hands embrace the lotus feet of the Lord and His associates. Thus the Lord is manifested to a pure devotee from within and without. This is one of the mysteries of the devotional relationship in which a devotee and the Lord are bound by a tie of spontaneous love. To achieve this love should be the goal of life for every living being.

From Srila Prabhupada’s purport to CC Adi 1.55