BG Chap 10 - The way Kṛṣṇa supports and maintains the creation
Having spoken of the vibhūtis individually, Kṛṣṇa speaks of them as a whole by saying there is no use of knowing all these individual vibhūtis because with a single fragment of Himself, He pervades and supports the entire universe. By the Paramātmā, fixing Himself in the world He created, supporting this world by being its basis, superintending the world by being its ruler, controlling the world by beings its controller (‘Everything is in Me’), pervading the world by being all pervading (‘I am in everything’), and creating the world by being its cause, Kṛṣṇa remains in this world. Kṛṣṇa does all these thru the three puruṣas, who are the antaryāmīs of prakṛti (Mahā-Viṣṇu), samaṣṭi-jīva (Garbhodakaśāyī Viṣṇu, who is the Supersoul of the collective jīvas) and vyaṣṭi-jīva (Kṣīrodakaśāyī Viṣṇu, who is the Supersoul in every jīva). Though there are three puruṣas, they are to be understood as just one of the parts of Kṛṣṇa. It should be understood that creation, containment, pervasion and maintenance are all vibhūtīs of Kṛṣṇa.