स वा एष आत्मा हृदि तस्यैतदेव निरुक्तं हृद्ययमिति तस्माद्धृदयमहरहर्वा एवंवित्स्वर्गं लोकमेति ॥ ३ ॥
In plain words
This very Self resides within the heart. Its very name, hṛdyayam, explains its nature: because it is in the heart, it is called the heart. Day after day, the one who knows this truth attains the radiant world of the infinite.
Close to the Sanskrit
This indeed is the Self in the heart. Of this is this very etymological derivation: 'hṛdyayam' (in the heart). Therefore it is the heart. Day by day indeed the knower thus reaches the heavenly world.