puruṣaḥ – Mahā-Viṣṇu, the master of the universe; sahasra-śīrṣā – has thousands of heads; sahasra-akṣaḥ – thousands of eyes; sahasra-pāt – thousands of feet; sahasra-bāhuḥ – thousands of arms; viśva-ātmā – He pervades the whole universe as the Supersoul; sahasra-aṁśaḥ – thousands of avatāra expansions; sahasra-sūḥ – and generates many thousands of living beings.
That master of the universe, Mahā-Viṣṇu, possesses thousands upon thousands of heads, thousands upon thousands of eyes, thousands upon thousands of arms, and thousands upon thousands of incarnations and plenary expansions. He is the Self of the cosmos, and He alone creates thousands upon thousands of living entities.
The form of Mahā-Viṣṇu is being described thus in the current verse beginning with the words sahasra-śirṣā. He whose innumerable incarnations appear in thousands upon thousands of plenary portions is called sahasrāṁśa. Similarly, He who creates thousands upon thousands of living entities is called sahasra-sūḥ. Here the word sahasra (one thousand) has been used to indicate an uncountable number. It is evident that the word sahasra is used throughout the scriptures to convey the sense of “innumerable.”
Furthermore, in describing the intrinsic form and nature of Mahā-Viṣṇu, it is stated in Śrīmad-Bhāgavatam (2.6.42): “The first avatāra of Bhagavān, the Lord of the spiritual realm, is the puruṣa who lies down in the Causal Ocean and casts His glance upon material nature. The following are all substances related to Parameśvara: His activities, such as the creation of time and acquired nature; material nature, which is composed of cause and effect; the unmanifest stage of material nature (mahat-tattva); the gross elements; false ego; the aggregate of the modes of material nature beginning with the mode of goodness manifested as various forms of life; hellish planets such as Pātālaloka; the aggregate of living entities; Garbhodakaśāyī Viṣṇu; moving and non-moving entities; and individual bodies.”
In the commentary to this verse, it is stated that the gigantic puruṣa, who instigates the activities of material nature, and who has thousands of heads and so on, has been called the original avatāra who assumes a pastime form. His activities include creation of the time factor, acquired nature and other elements of the material creation. Thus, the original puruṣa-avatāra creates, maintains and destroys within Himself and by Himself, at the beginning of every lifetime of Brahmā. Although He is one, He is manifest in many forms through His illusory energy. This universe, consisting of factual existence and the non-factual or temporary existence of cause and effect, is situated within Him alone. Therefore, all these phenomena have been called substances related to Him.
Mahā-Viṣṇu, who is praised throughout the Vedas, is replete with unlimited transcendental senses, and is characterized by endless power. That puruṣa is the origin of all incarnations.