it is by penance that the Rishis can read the Vedas without interruption. In the beginning the self-create caused those excellent Vedic sounds, that are embodiments of knowledge and that have neither beginning nor end. From those sounds have sprung all sorts of actions.
ऋषयस्तपसा वेदानध्यैषन्त दिवानिशम्। अनादिनिधना विद्या वागुत्सृष्टा स्वयम्भुवा।२४॥