Mbh 8.90.2b

The costly and bright armour also of the Suta's son that had been forged with great care by many foremost of artists working for a long time, the son of Pandu cut off within a moment in many fragments. After thus divesting him of his armour, Partha then, in rage, pierced Karna with four whetted shafts of great energy. Struck forcibly by his foe, Karna suffered great pain like a diseased person afflicted by bile, phlegm, wind, and fever. Once more Arjuna, with great speed, mangled Karna, piercing his very vitals, with numerous excellent shafts, of great keenness, and sped from his circling bow with much force and speed and care. Deeply struck by Partha with those diverse arrows of keen points and fierce energy, Karna (covered with blood) looked resplendent like a mountain of red chalk with streams of red water running down its breast. Once more Arjuna pierced Karna in the centre of the chest with many straight-coursing and strong shafts made entirely of iron and equipped with wings of gold and each resembling the fiery rod of the Destroyer, like the son of Agni piercing the Krauncha mountains. Then the Suta's son, casting aside his bow that resembled the very bow of Sakra, as also his quiver, felt great pain, and stood inactive, stupefied, and reeling, his grasp loosened and himself in great anguish. The virtuous Arjuna, observant of the duty of manliness, wished not to slay his enemy while fallen into such distress. The younger brother of Indra then, with great excitement, addressed him, saying, "Why, O son of Pandu, dost thou become so forgetful? They that are truly wise never spare their foes, however weak, even for a moment. He that is learned earneth both merit and fame by slaying foes fallen into distress. Lose no time in precipitately crushing Karna who is always inimical to thee and who is the first of heroes. The Suta's son, when able, will once more advance against thee as before. Slay him, therefore, like Indra slaying the Asura Namuci."