Viṣṇujana: "Kṛṣṇa in this form of Supersoul is situated in everyone's heart. Furthermore there is no difference between the innumerable Supersouls present in the innumerable hearts of living entities."
Prabhupāda: The example, just like there is one sun in the sky. But if you keep on the earth millions of waterpot, you'll find in each waterpot the reflection of the sun. Or another example, at noontime you just inquire from your friend, ten thousand miles away, "Where is the sun?" He'll say, "On my head." So millions and trillions of people will see sun on his head. But the sun is one. And another example, the waterpot. The sun is one, but if there are millions of waterpots you'll find in each pot the sun is reflected. Similarly there may be innumerable living entities. There is no count. Jīvasya asaṅkhya. In the Vedic language it is said that living entities, there is no count. Innumerable. So similarly Viṣṇu is, if a material thing like sun can be reflected in each and every waterpot, so why not the Supreme Personality of Godhead Viṣṇu live in each and everyone's heart. It is not difficult to understand. He's living. That is stated. And the yogi has to concentrate his mind on that Viṣṇu form. So this Viṣṇu form is plenary portion of Kṛṣṇa.