Śrīla Vyāsadeva is the great authority, and the subject matter of Śrīmad-Bhāgavatam being so important, he delivered the message first to his great son Śrīla Śukadeva Gosvāmī. It is compared to the cream of the milk. Vedic literature is like the milk ocean of knowledge. Cream or butter is the most palatable essence of milk, and so also is Śrīmad-Bhāgavatam, for it contains all palatable, instructive and authentic versions of different activities of the Lord and His devotees.
(Srimad Bhagavatam------1:3:41------purport).

When Brahmājī and other demigods want to consult Lord Viṣṇu, the plenary portion of Lord Kṛṣṇa, they have to wait on the shore of the ocean of milk where Lord Viṣṇu is lying on White Land (Śvetadvīpa).
(Srimad Bhagavatam------1:11:8------purport).

This ocean of milk and the Śvetadvīpa planet are the replica of Vaikuṇṭhaloka within the universe. Neither Brahmājī nor the demigods like Indra can enter into this island of Śvetadvīpa, but they can stand on the shore of the ocean of milkand transmit their message to Lord Viṣṇu, known as Kṣīrodakaśāyī Viṣṇu.
(Srimad Bhagavatam------1:11:8------purport).

As we have discussed many times, the Personality of Godhead Viṣṇu resides within each and every universe in two capacities, namely as the Garbhodakaśāyī Viṣṇu and the Kṣīrodakaśāyī Viṣṇu. The Kṣīrodakaśāyī Viṣṇu has His own planet on the northern top of the universe, and there is a great ocean of milk where the Lord resides on the bed of the Ananta incarnation of Baladeva. Thus Mahārāja Yudhiṣṭhira has compared the Yadu dynasty to the ocean of milk and Śrī Balarāma to the Ananta where Lord Kṛṣṇa resides.
(Srimad Bhagavatam------1:14:35-36-----purport).

Although it is not in our experience, there is a milk ocean within this universe. Even the modern scientist accepts that there are hundreds and hundreds of thousands of planets hovering over our heads, and each of them has different kinds of climatic conditions. Śrīmad-Bhāgavatam gives much information which may not tally with our present experience. But as far as Indian sages are concerned, knowledge is received from the Vedic literatures, and the authorities accept without any hesitation that we should look through the pages of authentic books of knowledge (śāstra-cakṣurvat).
(Srimad Bhagavatam------2:7:13------purport).

The gigantic work of churning the milk ocean by the combined effort of the demigods and the demons required a gigantic resting ground or pivot for the gigantic Mandara Hill. Thus to help the attempt of the demigods the primeval Lord assumed the incarnation of a gigantic tortoise, swimming in the ocean of milk. At the same time, the mountain scratched His backbone as He was partially sleeping and thus relieved His itching sensation.
(Srimad Bhagavatam------2:7:13------purport).

Those who do not believe in the existence of the ocean of milk because they have experience only of the salty water in the ocean should know that the world is also called the go, which means the cow. The urine of a cow is salty, and according to Āyur-vedic medicine the cow's urine is very effective in treating patients suffering from liver trouble. Such patients may not have any experience of the cow's milk because milk is never given to liver patients. But the liver patient may know that the cow has milk also, although he has never tasted it.
(Srimad Bhagavatam------3:2:8------purport).

From this ocean of milk the moon was born, but the fish in the milk ocean could not recognize that the moon. was not another fish and was different from them. The fish took the moon to be one of them or maybe something illuminating, but nothing more.
(Srimad Bhagavatam------3:2:8------purport).

Dhruva Mahārāja was offered Dhruvaloka, a planet that was never resided upon by any conditioned soul. Even Brahmā, although the topmost living creature within this universe, was not allowed to enter the Dhruvaloka. Whenever there is a crisis within this universe, the demigods go to see the Supreme Personality of Godhead Kṣīrodakaśāyī Viṣṇu, and they stand on the beach of the Milk Ocean. So the fulfillment of Dhruva Mahārāja's demand—a position more exalted than that of even his great-grandfather, Brahmā—was offered to him.
(Srimad Bhagavatam------4:9:29------purport).

Outside the ocean of clarified butter is another island, known as Krauñcadvīpa, which has a width of 1,600,000 yojanas (12,800,000 miles), twice the width of the ocean of clarified butter. As Kuśadvīpa is surrounded by an ocean of clarified butter, Krauñcadvīpa is surrounded by an ocean of milk as broad as the island itself. On Krauñcadvīpa there is a great mountain known as Krauñca, from which the island takes its name.
(Srimad Bhagavatam------5:20:18------translation).

Outside the ocean of milk is another island, Śākadvīpa, which has a width of 3,200,000 yojanas (25,600,000 miles). As Krauñcadvīpa is surrounded by its own ocean of milk, Śākadvīpa is surrounded by an ocean of churned yogurt as broad as the island itself. In Śākadvīpa there is a big śāka tree, from which the island takes its name. This tree is very fragrant. Indeed, it lends its scent to the entire island.
(Srimad Bhagavatam------5:20:24------translation).

By churning the ocean of milk, Ajita produced nectar for the demigods. In the form of a tortoise, He moved here and there, carrying on His back the great mountain known as Mandara.
(Srimad Bhagavatam------8:5:10------translation).

Concerning ajitasya padam, the abode of the Supreme Personality of Godhead in the milk ocean of this material world, Śrīla Viśvanātha Cakravartī Ṭhākura says: padaṁ kṣīrodadhi-stha-śvetadvīpaṁ tamasaḥ prakṛteḥ param. The island known as Śvetadvīpa, which is in the ocean of milk, is transcendental. It has nothing to do with this material world.
(Srimad Bhagavatam------8:5:24------purport).

The Supreme Personality of Godhead, who is known as Ajita, unconquerable, advised the demigods to make a peace proposal to the demons, so that after formulating a truce, the demigods and demons could churn the ocean of milk. The rope would be the biggest serpent, known as Vāsuki, and the churning rod would be Mandara Mountain. Poison would also be produced from the churning, but it would be taken by Lord Śiva, and so there would be no need to fear it.
(Srimad Bhagavatam------8:6------summary).

O demigods, cast into the ocean of milk all kinds of vegetables, grass, creepers and drugs. Then, with My help, making Mandara Mountain the churning rod and Vāsuki the rope for churning, churn the ocean of milk with undiverted attention. Thus the demons will be engaged in labor, but you, the demigods, will gain the actual result, the nectar produced from the ocean.
(Srimad Bhagavatam------8:6:22-23------translation).

A poison known as kālakūṭa will be generated from the ocean of milk, but you should not fear it. And when various products are churned from the ocean, you should not be greedy for them or anxious to obtain them, nor should you be angry.
(Srimad Bhagavatam------8:6:25------translation).

It appears that by the churning process many things would be generated from the ocean of milk, including poison, valuable gems, nectar and many beautiful women. The demigods were advised, however, not to be greedy for the gems or beautiful women, but to wait patiently for the nectar. The real purpose was to get the nectar.
(Srimad Bhagavatam------8:6:25------purport).

The goddess of fortune, mother Lakṣmījī, accepted the ocean of milk as her father, but she perpetually rests on the bosom of Nārāyaṇa. She offers benedictions even to Lord Brahmā and other living entities in this material world, yet she is transcendental to all material qualities. Although she appeared to have been born of the ocean of milk, she immediately resorted to her eternal place on the bosom of Nārāyaṇa.
(Srimad Bhagavatam------8:8:17------purport).

The goddess of fortune, Lakṣmīdevī, having been generated from the ocean of milk, was the daughter of the ocean. Thus she was allowed to select her own husband in a svayaṁvara ceremony. She examined every one of the candidates, but she could not find anyone suitably qualified to be her shelter. In other words, Nārāyaṇa, the natural husband of Lakṣmī, cannot be superseded by anyone in this material world.
(Srimad Bhagavatam------8:8:19------purport).

When Lord Śiva approached Lord Viṣṇu, Lord Viṣṇu inquired about the purpose for Lord Śiva's coming there. Now Lord Śiva discloses his desire. He wanted to see the recent incarnation of Mohinī-mūrti, which Lord Viṣṇu had assumed to distribute the nectar generated from the churning of the ocean of milk.
(Srimad Bhagavatam------8:12:12------purport).

Those who are obedient to the laws of God are protected by different servants and demigods, whereas those who are undesirable are vanquished by Lord Śiva. Lord Brahmā first met all the demigods, including Lord Śiva. Then, along with mother earth, they went to the shore of the ocean of milk, where Lord Viṣṇu lies on a white island, Śvetadvīpa.
(Srimad Bhagavatam------8:1:19------purport).

On the Vaikuṇṭha planet in every universe is an ocean of milk, and within that ocean is an island called Śvetadvīpa, where Lord Viṣṇu lives. Therefore this chapter describes two Śvetadvīpas-one in the abode of Kṛṣṇa and the other in the ocean of milk in every universe. The Śvetadvīpa in the abode of Kṛṣṇa is identical with Vṛndāvana-dhāma, which is the place where Kṛṣṇa appears Himself to display His loving pastimes. In the Śvetadvīpa within every universe is a Śeṣa form of Godhead who serves Viṣṇu by assuming the form of His umbrella, slippers, couch, pillows, garments, residence, sacred thread, throne and so on.
(Sri Caitanya Caritamrta------1:5------summary).

In Viṣṇuloka, which is above Satyaloka, Saṅkarṣaṇa resides. Mahā-saṅkarṣaṇa is another name of Saṅkarṣaṇa. Pradyumna lives in Dvārakā-pura, and Aniruddha lies on the eternal bed of Śeṣa, generally known as ananta-śayyā, on the island called Śvetadvīpa, in the ocean of milk.
(Sri Caitanya Caritamrta------1:5:40------purport).

Describing the features of the three puruṣas, the Laghu-bhāgavatāmṛta says that Garbhodakaśāyī Viṣṇu has a four-handed form, and when He Himself enters the hollow of the universe and lies down in the ocean of milk He is known as Kṣīrodakaśāyī Viṣṇu, who is the Supersoul of all living entities, including the demigods. In the Sātvata-tantra it is said that the third puruṣa incarnation, Kṣīrodakaśāyī Viṣṇu, is situated as the Supersoul in everyone's heart. This Kṣīrodakaśāyī Viṣṇu is an expansion of Garbhodakaśāyī Viṣṇu for pastimes.
(Sri Caitanya Caritamrta------1:5:93------purport).

In the Siddhānta-śiromaṇi, an astrological text, the different oceans are described as follows: (1) the ocean of salt water, (2) the ocean of milk, (3) the ocean of yogurt, (4) the ocean of clarified butter, (5) the ocean of sugarcane juice, (6) the ocean of liquor and (7) the ocean of sweet water. On the southern side of the ocean of salt water is theocean of milk, where Lord Kṣīrodakaśāyī Viṣṇu resides. He is worshiped there by demigods like Brahmā.
(Sri Caitanya Caritamrta------1:5:111------purport).

In the Brahmāṇḍa Purāṇa it is said, "The same Personality of Godhead who is known in Vaikuṇṭha as the four-handed Nārāyaṇa, the friend of all living entities, and in the milk ocean as the Lord of Śvetadvīpa, and who is the best of all puruṣas, appeared as the son of Nanda. In a fire there are many sparks of different dimensions; some of them are very big, and some are small. The small sparks are compared to the living entities, and the large sparks are compared to the Viṣṇu expansions of Lord Kṛṣṇa. All the incarnations emanate from Kṛṣṇa, and after the end of their pastimes they again merge with Kṛṣṇa."
(Sri Caitanya Caritamrta------1:5:132------purport).