Vritra said You and also other sages know full well the severe penances which I practised from greed of victory.
वृत्र उवाच प्रत्यक्षमेतद् भवतस्तथान्येषां मनीषिणाम्। मया यज्जयलुब्धेन पुरा तप्तं महत् तपः॥