The Absolute Truth is one but is perceived in three features, known as Brahman, Paramatma, and Bhagavan. The original, complete feature of the Absolute Truth is Bhagavan, the Supreme Personality of Godhead, and His plenary representation is Paramatma, Ksirodakasayi Viṣṇu, who is situated in everyone’s heart (isvarah sarva-bhutanam hrddese ‘rjuna tisthati). The third feature of the Absolute Truth is Brahman, the all-pervading impersonal effulgence of the Absolute. The Absolute Truth is equal to everyone, but one will realize the Absolute according to the way one approaches Him (ye yatha mam prapadyante). According to one’s capacity for understanding, the Absolute Truth is revealed either as the impersonal Brahman, as the localized Paramatma, or ultimately as Bhagavan.
By realizing the impersonal Brahman, one simply realizes the effulgence emanating from the transcendental body of Krishna. This effulgence is compared to the sunshine. There is the sun-god, the sun itself and the sunshine which is the shining effulgence of that original sun-god. Similarly, the spiritual effulgence (brahmjyoti), impersonal Brahman, is nothing but the personal effulgence of Krishna.
The Paramatma, the all-pervading feature situated in everyone’s body, is but a partial manifestation or expansion of Krishna, but because Krishna is the soul of souls, He is called Paramatma, the Supreme Self.
In the neutral stage of devotion, one may give more importance to the impersonal effulgence of the Lord and to the Supersoul within the heart, but Krishna consciousness actually develops when one thinks, “Krishna is my very intimate master of intimate relationships.” In the beginning, of course, impersonal realization and realization of the Supersoul are part of Krishna consciousness. The partial realization of God in His impersonal aspect or in His aspect as Supersoul enables one to develop veneration for the Lord, but when one has an intimate relationship with Krishna as a friend, master, son, or lover, then the veneration disappears.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Teachings of Queen Kunti”, Page 77
A.C. Bhaktivedanta Swami Prabhupada (2012 edition), “Teachings of Lord Caitanya, The Golden Avatara”, Page 78
A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “The Science of Self-Realization”, Page 352