Brihadaranyaka Upanishad 2.61

तदेतदृचाभ्यनूक्तम् — रूपं रूपं प्रतिरूपो बभूव तदस्य रूपं प्रतिचक्षणाय | इन्द्रो मायाभिः पुरुरूप ईयते युक्ता ह्यस्य हरयः शता दश ॥

tad etad richabhyanooktam — rupam rupam pratirrupo babhuva tad asya rupam praticchakshanaya | indro mayabhih pururupa iyate yukta hy asya harayah shata dasha ||

This is expressed in the Rik verse: 'He assumed form after form — each form of his was for the sake of making himself known. Indra through his powers of illusion goes about in many forms, for yoked to him are his ten hundred steeds.'

यह ऋचा में अभिव्यक्त है: 'वह रूप-रूप का प्रतिरूप बन गया — यह उसका रूप है प्रत्यक्ष देखने के लिए। इन्द्र माया से अनेक रूप धारण करता है — उसके अश्व जुते हुए हैं, दश सहस्र एक साथ।'