The Sanskrit word bhagavān is explained by the great authority Parāśara Muni, the father of Vyāsadeva. The Supreme Personality who possesses all riches, all strength, all fame, all beauty, all knowledge and all renunciation is called Bhagavān. There are many persons who are very rich, very powerful, very beautiful, very famous, very learned, and very much detached, but no one can claim that he possesses all riches, all strength, etc., entirely. Only Kṛṣṇa can claim this because He is the Supreme Personality of Godhead. No living entity, including Brahmā, Lord Śiva, or Nārāyaṇa, can possess opulences as fully as Kṛṣṇa. Therefore it is concluded in the Brahma-saṁhitā by Lord Brahmā himself that Lord Kṛṣṇa is the Supreme Personality of Godhead. No one is equal to or above Him. He is the primeval Lord, or Bhagavān, known as Govinda, and He is the supreme cause of all causes:
īśvaraḥ paramaḥ kṛṣṇaḥ
sac-cid-ānanda-vigrahaḥ
anādir ādir govindaḥ
sarva-kāraṇa-kāraṇam
"There are many personalities possessing the qualities of Bhagavān, but Kṛṣṇa is the supreme because none can excel Him. He is the Supreme Person, and His body is eternal, full of knowledge and bliss. He is the primeval Lord Govinda and the cause of all causes." (Brahma-saṁhitā 5.1)
(Bhagavad-Gita----2:2----purport).

In this millennium, the sun-god is known as Vivasvān, the king of the sun, which is the origin of all planets within the solar system. In the Brahma-saṁhitā (5.52) it is stated:
yac-cakṣur eṣa savitā sakala-grahāṇāṁ
rājā samasta-sura-mūrtir aśeṣa-tejāḥ
yasyājñayā bhramati sambhṛta-kāla-cakro
govindam ādi-puruṣaṁ tam ahaṁ bhajāmi
"Let me worship," Lord Brahmā said, "the Supreme Personality of Godhead, Govinda (Kṛṣṇa), who is the original person and under whose order the sun, which is the king of all planets, is assuming immense power and heat. The sun represents the eye of the Lord and traverses its orbit in obedience to His order."
(Bhagavad-Gita----4:1----purport).

Those who progress in Kṛṣṇa consciousness on the higher planets are gradually elevated to higher and higher planets and at the time of universal devastation are transferred to the eternal spiritual kingdom. Baladeva Vidyābhūṣaṇa, in his commentary on Bhagavad-gītā, quotes this verse:
brahmaṇā saha te sarve
samprāpte pratisañcare
parasyānte kṛtātmānaḥ
praviśanti paraṁ padam
"When there is devastation of this material universe, Brahmā and his devotees, who are constantly engaged in Kṛṣṇa consciousness, are all transferred to the spiritual universe and to specific spiritual planets according to their desires."
(Bhagavad-Gita----8:16----purport).

In Kali-yuga vice increases to such a point that at the termination of the yuga the Supreme Lord Himself appears as the Kalki avatāra, vanquishes the demons, saves His devotees, and commences another Satya-yuga. Then the process is set rolling again. These four yugas, rotating a thousand times, comprise one day of Brahmā, and the same number comprise one night. Brahmā lives one hundred of such "years" and then dies. These "hundred years" by earth calculations total to 311 trillion and 40 billion earth years. By these calculations the life of Brahmā seems fantastic and interminable, but from the viewpoint of eternity it is as brief as a lightning flash. In the Causal Ocean there are innumerable Brahmās rising and disappearing like bubbles in the Atlantic. Brahmā and his creation are all part of the material universe, and therefore they are in constant flux.
(Bhagavad-Gita----8:17----purport).

In the material universe not even Brahmā is free from the process of birth, old age, disease and death. Brahmā, however, is directly engaged in the service of the Supreme Lord in the management of this universe—therefore he at once attains liberation. Elevated sannyāsīs are promoted to Brahmā's particular planet, Brahmaloka, which is the highest planet in the material universe and which survives all the heavenly planets in the upper strata of the planetary system, but in due course Brahmā and all the inhabitants of Brahmaloka are subject to death, according to the law of material nature.
(Bhagavad-Gita----8:17----purport).

The less intelligent, who try to remain within this material world, may be elevated to higher planets and then again must come down to this planet earth. During the daytime of Brahmā they can exhibit their activities on higher and lower planets within this material world, but at the coming of Brahmā's night they are all annihilated. In the day they receive various bodies for material activities, and at night they no longer have bodies but remain compact in the body of Viṣṇu. Then again they are manifest at the arrival of Brahmā's day. Bhūtvā bhūtvā pralīyate (B.G.8:19): during the day they become manifest, and at night they are annihilated again. Ultimately, when Brahmā's life is finished, they are all annihilated and remain unmanifest for millions and millions of years. And when Brahmā is born again in another millennium they are again manifest.
(Bhagavad-Gita----8:19----purport).

The creation, maintenance and annihilation of this material cosmic manifestation are completely dependent on the supreme will of the Personality of Godhead. "At the end of the millennium" means at the death of Brahmā. Brahmā lives for one hundred years, and his one day is calculated at 4,300,000,000 of our earthly years. His night is of the same duration. His month consists of thirty such days and nights, and his year of twelve months. After one hundred such years, when Brahmā dies, the devastation or annihilation takes place; this means that the energy manifested by the Supreme Lord is again wound up in Himself.
(Bhagavad-Gita----9:7----purport).

The Lord is giving a genealogical synopsis of the universal population. Brahmā is the original creature born out of the energy of the Supreme Lord, who is known asHiraṇyagarbha. And from Brahmā all the seven great sages, and before them four other great sages, named Sanaka, Sananda, Sanātana and Sanat-kumāra, and the fourteen Manus, are manifested. All these twenty-five great sages are known as the patriarchs of the living entities all over the universe. There are innumerable universes and innumerable planets within each universe, and each planet is full of population of different varieties. All of them are born of these twenty-five patriarchs. Brahmā underwent penance for one thousand years of the demigods before he realized by the grace of Kṛṣṇa how to create. Then from Brahmā came Sanaka, Sananda, Sanātana and Sanat-kumāra, then Rudra, and then the seven sages, and in this way all the brāhmaṇas and kṣatriyas are born out of the energy of the Supreme Personality of Godhead. Brahmā is known as Pitāmaha, the grandfather, and Kṛṣṇa is known as Prapitāmaha, the father of the grandfather. That is stated in the Eleventh Chapter of the Bhagavad-gītā (11.39).
(Bhagavad-Gita----10:6----purport).

Arjuna said: My dear Lord Kṛṣṇa, I see assembled in Your body all the demigods and various other living entities. I see Brahmāsitting on the lotus flower, as well as Lord Śiva and all the sages and divine serpents.
Arjuna sees everything in the universe; therefore he sees Brahmā, who is the first creature in the universe, and the celestial serpent upon which the Garbhodakaśāyī Viṣṇu lies in the lower regions of the universe. This snake bed is called Vāsuki. There are also other snakes known as Vāsuki. Arjuna can see from the Garbhodakaśāyī Viṣṇu up to the topmost part of the universe on the lotus-flower planet where Brahmā, the first creature of the universe, resides. That means that from the beginning to the end, everything could be seen by Arjuna, who was sitting in one place on his chariot. This was possible by the grace of the Supreme Lord, Kṛṣṇa.
(Bhagavad-Gita----11:15----translation and purport).

O great one, greater even than Brahmā, You are the original creator. Why then should they not offer their respectful obeisances unto You? O limitless one, God of gods, refuge of the universe! You are the invincible source, the cause of all causes, transcendental to this material manifestation.
By this offering of obeisances, Arjuna indicates that Kṛṣṇa is worshipable by everyone. He is all-pervading, and He is the Soul of every soul. Arjuna is addressing Kṛṣṇa as mahātmā, which means that He is most magnanimous and unlimited. Ananta indicates that there is nothing which is not covered by the influence and energy of the Supreme Lord, and deveśa means that He is the controller of all demigods and is above them all. He is the shelter of the whole universe. Arjuna also thought that it was fitting that all the perfect living entities and powerful demigods offer their respectful obeisances unto Him, because no one is greater than Him. Arjuna especially mentions that Kṛṣṇa is greater than Brahmā because Brahmā is created by Him. Brahmā is born out of the lotus stem grown from the navel abdomen of Garbhodakaśāyī Viṣṇu, who is Kṛṣṇa's plenary expansion; therefore Brahmā and Lord Śiva, who is born of Brahmā, and all other demigods must offer their respectful obeisances. It is stated in Śrīmad-Bhāgavatam that the Lord is respected by Lord Śiva and Brahmā and similar other demigods.
(Bhagavad-Gita----11:37----translation and purport).

As the sun exists diffusing its unlimited rays, so does the Supersoul, or Supreme Personality of Godhead. He exists in His all-pervading form, and in Him exist all the individual living entities, beginning from the first great teacher, Brahmā, down to the small ants.
(Bhagavad-Gita----13:14----purport).