Both Karna and Moses were cast off into rivers by their mothers and it was their brothers- Arjuna in the case of Karna and Aaron in the case of Moses whose lineages were consecrated as Kings in the Indian tradition and High Priests (kohainim) in the Judaic.
It has been speculated that the motif of the baby cast away in a reed basket is a very ancient one- perhaps one with some historical precedent in the case of Sargon of Akkad- and that it might have been used to disguise the genealogical identity of a usurper or a person of different ethnic or class background. Freud's notion that Moses might have been an Egyptian follower of Akhenaton is a famous example of this sort of Euhemerism.
In the case of the Mahabharata, it is tempting to look at Karna- whose dominating quality is unbounded generosity arising from an overmastering thymotic (rajsic) drive- as a foil to Yuddhishtra whose predominating quality is forbearance and respect for the rights of others. Perhaps, Karna represents an older conception of the chivalrous Hero-King which was ceasing to be prescriptive in a materially more prosperous age when the important thing was to develop trade-routes, commercial networks and secure the possessions of the productive classes by establish an indefeasible code of Law as opposed to the Justice-as-patronage model of the early Iron Age.
The pathos of Karna, as one who prefers that the great warriors get one last chance to gain heaven in a battle to end all battles, is the pathos of the Gloaming of the Age of Heroes which will leave Epic Poetry forever widowed.
In contrast, the pathos of Moses- taking his last look from Pisgah upon the Promised Land he is forbidden to enter; his own seed fated to receive no special recognition though that of his brother Aaron remains distinguished to this day by the title Cohen, or Kahane- marks something new in the world of letters- it is the raising of Prophesy to the level of Prose, it is the birth of a Bibliolatry which will hunt down bards, it is the final withdrawal of the heimat of human belonging from what henceforth will be merely land.
Karna is not vanquished any more than the Winter Sun is vanquished by hoar frost. Moses, on the other hand, never enters the Promised Land. A book binds him. Black ink stronger than that Red Sea he vainly parted.