चतुर्थः प्रपाठकः ॥द्विधा वा एष आत्मानं बिभर्त्ययं यः प्राणो यश्चासावादित्योऽथ द्वौ वा एतावास्तां पञ्चधा नामान्तर्बहिश्चाहोरात्रे तौ व्यावर्तेते असौ वा आदित्यो बहिरात्मान्तरात्मा प्राणो बहिरात्मा गत्यान्तरात्मनानुमीयते ।गतिरित्येवं ह्याह यः कश्चिद्विद्वानपहतपाप्माध्यक्षोऽवदातमनास्तन्निष्ठ आवृत्तचक्षुः सोऽन्तरात्मागत्या बहिरात्मनोऽनुमीयते गतिरित्येवं ह्याहाथ य एषोऽन्तरादित्ये हिरण्मयः पुरुषो यः पश्यति मां हिरण्यवत्स एषोऽन्तरे हृत्पुष्कर एवाश्रितोऽन्नमत्ति ॥५.१ ॥
In plain words
This Self bears itself in two ways: as this breath, and as that sun yonder. And these two are its two paths, within and without; they turn about as day and night. That sun is the outer self, and the breath is the inner self. The outer self is inferred by the going of the inner self. So it is said: "Whoever is a knower, whose evil is struck away, an overseer, of clear mind, established in that, with his eye turned inward — he is the inner self." The outer self is inferred by the going of the inner self; so it is said. And the golden person within the sun, who looks down upon this earth as though upon gold — he is the one who, seated in the lotus of the heart within, eats food.