Bhashya
किंच, अरा इव यथा रथनाभौ समर्पिता अरा , एव संहता संप्रविष्टा यत्र यस्मिन्हृदये सर्वतो देहव्यापिन्य नाड्य , तस्मिन्हृदये बुद्धिप्रत्ययसाक्षिभूत स एष प्रकृत आत्मा अन्त मध्ये चरते चरति वर्तते ।पश्यन् शृण्वन्मन्वानो विजानन् बहुधा अनेकधा क्रोधहर्षादिप्रत्ययैर्जायमान इव जायमान अन्त करणोपाध्यनुविधायित्वात् , वदन्ति हि लौकिका हृष्टो जात क्रुद्धो जात इति ।तमात्मानम् ओमित्येवम् ओंकारालम्बना सन्त यथोक्तकल्पनया ध्यायथ चिन्तयत ।उक्त च वक्तव्य शिष्येभ्य आचार्येण जानता ।शिष्याश्च ब्रह्मविद्याविविदिषुत्वान्निवृत्तकर्माणो मोक्षपथे प्रवृत्ता ।तेषां निर्विघ्नतया ब्रह्मप्राप्तिमाशास्त्याचार्य — स्वस्ति निर्विघ्नमस्तु व युष्माकं पाराय परकूलाय , कस्य ? अविद्यातमस परस्तात् , अविद्यारहितब्रह्मस्वरूपगमनायेत्यर्थ ॥
In plain words
Just as the spokes are anchored in the hub of a chariot wheel, all the subtle channels of the body converge within the heart. In that very heart resides the Atman, the pure witness of all mental states. Appearing to act—seeing, hearing, thinking, and knowing—and seeming to take birth in various ways through passing emotions like joy and anger (for people say 'he has become happy' or 'he has become angry'), this Self dwells within. Meditate upon that Atman using the single syllable Om as your support, precisely as instructed. The enlightened teacher imparts this to his students who, having turned away from worldly actions and longing for the knowledge of Brahman, have entered the path of freedom. Wishing them an unobstructed journey to the ultimate goal, the teacher offers this blessing: 'May you safely cross to the farther shore—beyond the darkness of ignorance—and realize your true nature as Brahman.'
Close to the Sanskrit
Moreover, as spokes are fitted in the navel of a chariot wheel, so they are gathered and entered where in the heart channels pervading the body from all sides are, in that heart the witness of intellect-modifications, this one the subject Atman inside moves, seeing, hearing, thinking, knowing, appearing to be born in manifold ways through emotional modifications like joy and anger, for people say 'he has become joyful, he has become angry'. That Atman meditate upon with Om alone, having Om as support according to the prescription. And it is spoken to the disciples by the knowing teacher. The disciples, desiring knowledge of Brahman, having renounced actions, are established on the path of liberation. The teacher blesses them for their unobstructed attainment of Brahman: may there be safety for you for the crossing, to the other bank, of what? Beyond the darkness of ignorance, meaning for attaining the nature of Brahman free from ignorance.