Mahabharata 1.71.20
वैशंपायन उवाच · vaiśaṃpāyana uvāca
कचस्तु तं तथेत्युक्त्वा प्रतिजग्राह तद्व्रतम्आदिष्टं कविपुत्रेण शुक्रेणोशनसा स्वयम्
kacastu taṃ tathetyuktvā pratijagrāha tadvratamādiṣṭaṃ kaviputreṇa śukreṇośanasā svayam
Our plain-language meaning of this verse is waiting for scholar review.