SB 5.17.14
navasv api varsesu bhagavan narayano maha-purusah purusanam tad-anugrahayatma-tattva-vyuhenatmanadyapi
sannidhiyate.
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
To show mercy to His devotees in each of these nine tracts of land, the Supreme Personality of Godhead known as Narayana expands Himself in His quadruple principles of Vasudeva, Sankarsana, Pradyumna and Aniruddha. In this way He remains near His devotees to accept their service.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In this connection, Visvanatha Cakravarti Thakura informs us that the demigods worship the Supreme Lord in His various Deity forms (arca-vigraha) because except in the spiritual world, the Supreme Personality of Godhead cannot be directly worshiped in person. In the material world, the Lord is always worshiped as the arca-vigraha, or Deity in the temple. There is no difference between the arca-vigraha and the original person, and therefore those who are engaged in worshiping the Deity in the temple in full opulence, even on this planet, should be understood to be directly in touch with the Supreme Personality of Godhead without a doubt. As enjoined in the sastras, arcye visnau sila-dhir gurusu nara-matih: “No one should treat the Deity in the temple as stone or metal, nor should one think that the spiritual master is an ordinary human being.” One should strictly follow this sastric injunction and worship the Deity, the Supreme Personality of Godhead, without offenses. The spiritual master is the direct representative of the Lord, and no one should consider him an ordinary human being. By avoiding offenses against the Deity and the spiritual master, one can advance in spiritual life, or Krsna consciousness.
In this regard, the following quotation appears in the Laghu-bhagavatamrta:
padme tu parama-vyomnah
purvadye dik-catustaye
vasudevadayo vyuhas
catvarah kathitah kramat
tatha pada-vibhutau ca
nivasanti kramadi me
jalavrti-stha-vaikuntha-
sthita vedavati-pure
satyordhve vaisnave loke
nityakhye dvaraka-pure
suddhodad uttare sveta-
dvipe cairavati-pure
ksirambudhi-sthitante
kroda-paryanka-dhamani
satvatiye kvacit tantre
nava vyuhah prakirtitah
catvaro vasudevadya
narayana-nrsimhakau
hayagrivo maha-krodo
brahma ceti navoditah
tatra brahma tu vijñeyah
purvokta-vidhaya harih
“In the Padma Purana it is said that in the spiritual world the Lord personally expands in all directions and is worshiped as Vasudeva, Sankarsana, Pradyumna and Aniruddha. The same God is represented by the Deity in this material world, which is only one quarter of His creation. Vasudeva, Sankarsana, Pradyumna and Aniruddha are also present in the four directions of this material world. There is a Vaikunthaloka covered with water in this material world, and on that planet is a place called Vedavati, where Vasudeva is located. Another planet known as Visnuloka is situated above Satyaloka, and there Sankarsana is present. Similarly, in Dvaraka-puri, Pradyumna is the predominator. On the island known as Svetadvipa, there is an ocean of milk, and in the midst of that ocean is a place called Airavati-pura, where Aniruddha lies on Ananta. In some of the satvata-tantras, there is a description of the nine varsas and the predominating Deity worshiped in each: (1) Vasudeva, (2) Sankarsana, (3) Pradyumna, (4) Aniruddha, (5) Narayana, (6) Nrsimha, (7) Hayagriva, (8) Mahavaraha, and (9) Brahma.” The Lord Brahma mentioned in this connection is the Supreme Personality of Godhead. When there is no fit human being to empower as Lord Brahma, the Lord Himself takes the position of Lord Brahma. Tatra brahma tu vijñeyah purvokta-vidhaya harih. That Brahma mentioned here is Hari Himself.