Chandogya Upanishad 3.12

ते वा एतेऽथर्वाङ्गिरस एतदितिहासपूराणमभ्यतपꣳस्तस्याभितप्तस्य यशस्तेज इन्द्रियं वीर्यमन्नाद्यꣳरसोऽजायत ॥ २ ॥

3.4.2 — te va ete'tharvangirasa etaditihasapuranamabhyatapamstasyabhitaptasya yashasteja indriyam viryamannadyamraso'jayata || 2 ||

Verily, those [Hymns] of the Atharvans and Angirases brooded upon that Legend and Ancient Lore. From it, when it had been brooded upon, there was produced as its essence splendor, brightness, power, vigor, and food.

उन अथर्वाङ्गिरसों ने इस इतिहास-पुराण-पुष्प पर तप किया; इस प्रकार अभितप्त हुए उस पुष्प से यश, तेज, इन्द्रिय-बल, वीर्य तथा अन्नाद्य रस उत्पन्न हुआ।