Mbh 5.169.1

“‘Bhishma said, “Both the brothers Achala and Vrisha are Rathas. Invincible (in battle) they will slay thy foes. Endued with great strength, those tigers among men, those foremost of Gandharvas, are firm in wrath. Young and handsome, they are possessed of great strength. As regards this thy ever dear friend, this one who is always boastful of his skill in battle, this one who always urgeth thee, O king, to fight with the Pandavas, this vile braggart, Karna, the son of Surya, this one who is thy counsellor, guide, and friend, this vain wight who is destitute of sense, this Karna, is neither a Ratha nor an Atiratha. Without sense, this one hath been deprived of his natural coat of mail. Always kind, he hath also been deprived of his celestial ear-rings. In consequence of the curse of Rama (his preceptor in arms) as also of the words of a Brahmana (who cursed him on another occasion), owing also to his deprivation of the accoutrements of battle, he, in my judgment, is only half a Ratha. Having approached Falguni (in battle), he will not certainly escape with life!” Hearing this, Drona, that foremost of all wielders of weapons, said, “It is even so as thou hast said. That is not untrue! He boasteth on the eve of every battle, but yet he is seen to retreat from every engagement. Kind (out of season) and blundering, it is for this that Karna, in my judgment, is only half a Ratha!”