Mbh 8.24.1d

Then Nakula, steedless and carless and armourless, O monarch, quickly alighting from his car, stood, armed with a spiked bludgeon. Even that terrible bludgeon, so uplifted by the son of Pandu, the Suta's son, O king, cut off with many keen arrows capable of bearing a great strain. Beholding his adversary weaponless. Karna began to strike him with many straight shafts, but took care not to afflict him greatly. Thus struck in that battle by that mighty warrior accomplished in weapons, Nakula, O king, fled away precipitately in great affliction. Laughing repeatedly, the son of Radha pursued him and placed his stringed bow, O Bharata, around the neck of the retreating Nakula. With the large bow around his neck, O king, the son of Pandu looked resplendent like Moon in the firmament when within a circular halo of light, or a white cloud girdled round by Indra's bow. Then Karna, addressing him, said, "The words thou hadst uttered were futile. Canst thou utter them now once more in joy, repeatedly struck as thou art by me? Do not, O son of Pandu, fight again with those amongst the Kurus that are possessed of greater might. O child, fight with them that are thy equals. Do not, O son of Pandu, feel any shame for it. Return home, O son of Madri, or go thither where Krishna and Phalguna are." Having addressed him thus he abandoned him then. Acquainted with morality as the brave Karna was, he did not then slay Nakula who was already within the jaws of death. Recollecting the words of Kunti, O king, Karna let Nakula go. The son of Pandu, thus let off, O king, by that bowman, Suta's son, proceeded towards Yudhishthira's car in great shame. Scorched by the Suta's son, he then ascended his brother's car, and burning with grief he continued to sigh like a snake kept within a jar. Meanwhile Karna, having vanquished Nakula, quickly proceeded against the Pancalas, riding on that car of his which bore many gorgeous pennons and whose steeds were as white as the Moon.