Talk 47, Ch 4, Ma 16-17, Svetaswatara Upanishad

He who knows Siva, the blissful one, who is hidden in all beings in an extremely subtle form, finer than the essence of ghee, who alone envelops the universe, is freed from all fetters.
That God, the creator of the universe, the supreme soul, always dwells in the heart of all beings, being limited by the heart, intellect and mind. Those who know this become immortal.