Mahabharata 5.73.1

वैशंपायन उवाच · vaiśaṃpāyana uvāca

एतच्छ्रुत्वा महाबाहुः केशवः प्रहसन्निवअभूतपूर्वं भीमस्य मार्दवोपगतं वचः

etacchrutvā mahābāhuḥ keśavaḥ prahasannivaabhūtapūrvaṃ bhīmasya mārdavopagataṃ vacaḥ

Our plain-language meaning of this verse is waiting for scholar review.