Srimad Bhagavatam 10.14.55-57

You should know Kṛṣṇa to be the original Soul of all living entities. For the benefit of the whole universe, He has, out of His causeless mercy, appeared as an ordinary human being. He has done this by the strength of His internal potency. Those in this world who understand Lord Kṛṣṇa as He is see all things, whether stationary or moving, as manifest forms of the Supreme Personality of Godhead. Such enlightened persons recognize no reality apart from the Supreme Lord Kṛṣṇa. The original, unmanifested form of material nature is the source of all material things, and the source of even that subtle material nature is the Supreme Personality of Godhead, Kṛṣṇa. What, then, could one ascertain to be separate from Him.