Garbhodakaśāyī Visnu (Hiraņyagarbha) is an expansion of Mahā-Visnu (Kāraṇodakaśāyī Visnu).

In Gaudīya Vaisnavism the Sātvata-tantra describes three different forms of Visnu as- 

1 - Mahā-Visnu who is also known as Kāraṇodakaśāyī Visnu. 

2 - Garbhodakaśāyī Visnu also known as Hiraņyagarbha. 

3 - Ksirodakaśāyī Visnu also known as Paramātmā and Supersoul. 

Deep inside the massive Brahmanda material universe that Mahā-Viṣṇu creates in unlimited numbers, is a "secondary material universe" where Mahā-Viṣṇu expands Himself as Garbhodakashayi Visnu. 

From Garbhodakashayi Visnu  comes Lord Brahma who sits on the top of a lotus flower at the end of its stem, that grows from the naval of Garbhodakaśāyī Visnu. 

Lord Brahma then creates 14 different material planetary systems including all the administrator's (demigods) for this material universe, which as said above, is just one material universe out of billions of "secondary material universes" found deep inside their massive Brahmanda universal shell.

Each of the three Visnus have different roles in the maintenance of the material universe and its inhabitants.

Srila Prabhupada - "For material creation, Lord Krsna's plenary expansion assumes the three Visnus. 

1 - The first, Mahā-Viṣṇu or Kāraṇodakaśāyī Visnu, creates the total material energy known as the mahat-tattva. 

2 - The second, Garbhodakaśāyī Viṣṇu, enters into all the secondary universes inside their Brahmanda to create diversities.

3 - The third, Kṣīrodakaśāyī Visnu, is diffused as the all-pervading supersoul in all the universes; in the heart of every living being known as Paramātmā. 

Lord Visnu is present even within the material atoms.

The real objective of meditation in yoga is attaining a state of Paramātmā. Anyone who realises them can be liberated from material entanglement.

Sātvata-tantra - Books or literature of devotional service by Srila Prabhupada.

Garbhodakaśāyī Viṣṇu is an expansion of Mahā-Viṣṇu (expansion of Sankarṣaṇa of second caturvyūha, who expands from Nārāyaṇa from the Vaikuṇṭha planets in the spiritual world. The latter is realized as the expansion of Pradyumna.

Srila Prabhupada - "The three puruṣa-avatāras are described in Śrīmad-Bhāgavatam. They are also described in the Sātvata-tantra. 

Viṣṇus tu trīṇi rūpāṇi puruṣākhyāny atho viduḥ: the Supreme Personality of Godhead manifests three feature as-

Kāraṇodakaśāyī Viṣṇu (Maha-Visnu),

Garbhodakaśāyī Viṣṇu (Hiraņyagarbha) 

Kṣīrodakaśāyī Viṣṇu (Paramatma and Supersoul) 

Mahā-Viṣṇu, or Kāraṇodakaśāyī Viṣṇu is described in the Brahma-saṁhitā (5.47). Yaḥ kāraṇārṇava-jale bhajati sma yoga-nidrām- 

The Supreme Lord Kṛṣṇa is the cause of all causes, He lies down in the cosmic ocean as Mahā-Viṣṇu. Therefore, the Supreme Personality of Godhead is the beginning of this universe, the maintainer of the universal manifestations, and the end of all energy." (BG, Ch 10 text 20 purport).

Srila Prabhupada - "All the innumerable material universes (Brahmandas) enter the Body of Mahā-Viṣṇu, into whom they eventually again come forth again simply by His breathing process. He is a plenary expansion of Kṛṣṇa. Therefore, I worship Govinda, Kṛṣṇa, the cause of all causes. 

One should conclusively worship the personal form of Kṛṣṇa as the Supreme Personality of Godhead who has eternal bliss and knowledge. Krsna is the source of all forms of Viṣṇu, He is the source of all forms of incarnation, and He is the original Supreme Personality, as confirmed in Bhagavad-gītā." (BG, Ch 11 text 54 purport).

Srila Prabhupada - "This part of the spiritual sky called the mahat-tattva (material energy), is only an insignificant portion of the whole spiritual sky, and deep within this mahat-tattva there are innumerable universes. All these universes are collectively produced by the Kāraṇodakaśāyī Viṣṇu, also called Mahā-Viṣṇu, who simply throws His glance to impregnate the material sky." (SB, Canto 1 Ch 3 text 1 purport).

Srila Prabhupada - "They can see only the circular sky overhead, without any information that this material universe, as well as many other hundreds of thousands of universes, are each covered by sevenfold material coverings of-

earth,

water, 

fire, 

air, 

sky, 

the total energy,  

ego, 

noumenon and material nature, just like a huge football, pumped and covered, floating on the water of the Causal Ocean, wherein the Lord is lying as Mahā-Viṣṇu. All the material universes in seed are emanating from the breathing of the Mahā-Viṣṇu, who is but part of a partial expansion of the Lord, and all the universes presided over by the Brahmās vanish when the Mahā-Viṣṇu withdraws His great breath. In this way, the material worlds are being created and vanished by the supreme will of the Lord." (SB, Canto 2 Ch 1 text 25 purport).

Srimad Bhagavatam - "Every universe is covered by seven layers—earth, water, fire, air, sky, the total energy and false ego—each ten times greater than the previous one. There are innumerable universes besides this one, and although they are unlimitedly large, they move about like atoms in You. Therefore You are called unlimited [ananta]." (SB, Canto 6 Ch 16 text 37)

Srila Prabhupada - "The Brahma-saṁhitā (5.48) says:

yasyaika-niśvasita-kālam athāvalambya

jīvanti loma-vilajā jagad-aṇḍa-nāthāḥ

viṣṇur mahān sa iha yasya kalā-viśeṣo

govindam ādi-puruṣaṁ tam ahaṁ bhajāmi

The origin of the material creation is Mahā-Viṣṇu, who lies in the Causal Ocean. While He sleeps in that ocean, millions of universes are generated as He exhales, and they are all annihilated when He inhales. 

This Mahā-Viṣṇu is a plenary portion of a portion of Viṣṇu, Govinda (yasya kalā-viśeṣaḥ). The word kalā refers to a plenary portion of a plenary portion. 

From Kṛṣṇa, or Govinda, comes Balarāma; from Balarāma comes Saṅkarṣaṇa; from Saṅkarṣaṇa, Nārāyaṇa; from Nārāyaṇa, the second Saṅkarṣaṇa; from the second Saṅkarṣaṇa, Mahā-Viṣṇu; from Mahā-Viṣṇu, Garbhodakaśāyī Viṣṇu; and from Garbhodakaśāyī Viṣṇu, Kṣīrodakaśāyī Viṣṇu. 

Kṣīrodakaśāyī Viṣṇu controls every universe. This gives an idea of the meaning of ananta, unlimited. What is to be said of the unlimited potency and existence of the Lord? 

This verse describes the coverings of the universe (saptabhir daśa-guṇottarair aṇḍa-kośaḥ). 

The first covering is earth, the second is water, the third is fire, the fourth is air, the fifth is sky, the sixth is the total material energy, and the seventh is the false ego. 

Beginning with the covering of earth, each covering is ten times greater than the previous one. Thus we can only imagine how great each universe is, and there are many millions of universes. As confirmed by the Lord Himself in Bhagavad-gītā (10.42):

athavā bahunaitena

kiṁ jñātena tavārjuna

viṣṭabhyāham idaṁ kṛtsnam

ekāṁśena sthito jagat

“But what need is there, Arjuna, for all this detailed knowledge? With a single fragment of Myself I pervade and support this entire universe.” 

The entire material world manifests only one fourth of the Supreme Lord’s energy. Therefore He is called ananta." (SB, Canto 6 Ch 16 text 37 Purport)

Srila Prabhupada - "He expands Himself by His different energies, as well as by His plenary portions. In a corner of the spiritual sky of brahmajyoti a spiritual cloud sometimes appears, and the covered portion is called the mahat-tattva (material world). The Lord then, by His plenary portion as Mahā-Viṣṇu, lies down within the water of the mahat-tattva, and the water is called the Causal Ocean (Kāraṇa-jala). 

While Mahā-Viṣṇu sleeps within the Causal Ocean, innumerable universes are generated along with His breathing. These universes are floating, and they are scattered all over the Causal Ocean. They stay only during the breathing period of Mahā-Viṣṇu. In each and every universal globe, the same Mahā-Viṣṇu enters again as Garbhodakaśāyī Viṣṇu and lies there on the serpentlike Śeṣa incarnation. 

From His navel sprouts a lotus stem, and on the lotus, Brahmā, the lord of the universe, is born. Brahmā then "creates all material  bodily forms or vessels for the 8 million 400 thousand species of individual eternal life forms or living entities to satisfy different desires within the material  universe. He also creates the sun, moon and other demigods." (SB, Canto 2 Ch 5 text 33 purport).

Srila Prabhupada - "In the Bṛhad-āraṇyaka Upaniṣad (1.4.1) there is the hymn ātmaivedam agra āsīt puruṣa-vidhaḥ. 

This mantra indicates the Supreme Personality of Godhead (Kṛṣṇa) even before the appearance of the puruṣa incarnation. In the Bhagavad-gītā (15.18) it is said that Lord Kṛṣṇa is Puruṣottama because He is the supreme puruṣa, transcendental even to the puruṣa-akṣara and the puruṣa-kṣara. 

The akṣara-puruṣa, or the Mahā-Viṣṇu, throws His glance over prakṛti, or material nature, but the Puruṣottama existed even before that. 

The Bṛhad-āraṇyaka Upaniṣad therefore confirms the statement of the Bhagavad-gītā that Lord Kṛṣṇa is the Supreme Person (Puruṣottama)." (SB, Canto 2 Ch 9 text 33 purport).

Srila Prabhupada - "There are three different types of creation, called- 

mahā-kalpa, 

vikalpa, 

kalpa. 

In the mahā-kalpa the Lord assumes the first puruṣa incarnation as Kāraṇodakaśāyī Viṣṇu with all the potencies of the mahat-tattva (material nature) and the sixteen principles of creative matter and instruments. The creative instruments are eleven, the ingredients are five, and all of them are products of mahat, or materialistic ego. These creations by the Lord in His feature of Kāraṇodakaśāyī Viṣṇu are called mahā-kalpa. 

The creation of Brahmā and dispersion of the material ingredients are called vikalpa, and the creation by Brahmā in each day of his life is called kalpa. Therefore, each day-time of Brahmā is called a kalpa, and so is his night-time (2 kalpas every 24 hours) and there are thirty kalpas in terms of Brahmā's days."(SB, Canto 2 Ch 10 text 46 purport).

Srila Prabhupada - "Every living being (Visnu-tattva, Siva-tattva and jiva-tattva) is controlled by the supreme living being Krsna, and Paramātmā resides within every jiva-tattva (jiva-souls) heart. He is the puruṣa, the puruṣa-avatāra, who creates this material world. The first puruṣa-avatāra is Mahā-Viṣṇu, and that Mahā-Viṣṇu is the plenary portion of the plenary portion of the Supreme Personality of Godhead, Kṛṣṇa. Kṛṣṇa's first expansion is Baladeva (Balarama), and His next expansions are-

Balarama (Baladeva) 

Vāsudeva, 

Saṅkarṣaṇa, 

Aniruddha,

Pradyumna. (SB, Canto 5 Ch 11 text 13-14 purport).

Srila Prabhupada - "Kṛṣṇa is the origin of all viṣṇu-tattvas, including- 

Mahā-Viṣṇu, 

Garbhodakaśāyī Viṣṇu, 

Kṣīrodakaśāyī Viṣṇu. 

He is the ultimate goal of Vaiṣṇava philosophy, everything emanates from Kṛṣṇa. His body is completely spiritual and is the source of all spiritual being. (CC, 2:20:153 purport).**

Compiled by Gauragopala Dasa Acbsp (initiated by Srila Prabhupada on July 10th 1972).