God is situated in everyone's heart. Simply you do not know. He is situated. He is everywhere. Within the atom also, He is present. Andantarastham paramanu cayantarastham (Bs. 5.35). God is present within this world, within everything, everywhere, even within the atom. Now, at the present moment, the atomic theory is very prominent, but in the Vedic literature it is said that God is existing even within the atom. Aṇḍāntara-stha-paramāṇu. Paramāṇu means atom. Therefore īśvaraḥ sarva-bhūtānāṁ hṛd-deśe 'rjuna tiṣṭhati (BG 18.61).
Īśvara, the Supreme Lord, is sitting within your heart. I am also sitting. This is dress. This body is dress, but my place is within the heart. The medical science also says all the energy is coming from the heart. The heart stops to work, that means man is dead. So the soul and the Supersoul both are sitting in the heart.
We get this information from Vedic literature. So as soon as we begin hearing about the Supersoul or the Supreme Lord, then the contamination which are accumulated on the covering of our heart for so many years of our past birth, by simply hearing, by electrifying or by lighting, it becomes clear. Śṛṇvatāṁ sva-kathāḥ kṛṣṇaḥ puṇya-śravaṇa-kīrtanaḥ (SB 1.2.17).
To hear about God is itself a pious activity. Even if we do not understand, simply if we hear this chanting, Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma . . . one becomes gradually a pious man. Apart from any other realization, he becomes a pious man. In this way, as soon as we hear about God, we become cleansed of all material contamination.