CHĀNDOGYA UPANISHAD · 4.16.5

स यथोभयपाद् व्रजन् रथो वोभाभ्यां चक्राभ्यां वर्तमानः प्रतितिष्ठत्य् एवम् अस्य यज्ञः प्रतितिष्ठति यज्ञं प्रतितिष्ठन्तं यजमानो ऽनु प्रतितिष्ठति ।
स इष्ट्वा श्रेयान् भवति ॥

sa yathobhayapād vrajan ratho vobhābhyāṃ cakrābhyāṃ vartamānaḥ pratitiṣṭhaty evam asya yajñaḥ pratitiṣṭhati yajñaṃ pratitiṣṭhantaṃ yajamāno ’nu pratitiṣṭhati ।
sa iṣṭvā śreyān bhavati ॥

As a man walking on two legs and a carriage going on two wheels gets on, so his sacrifice gets on, and with the successful sacrifice the sacrificer gets on; yes, having sacrificed, he becomes better.

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)