Karna Parva 1.22

As, O twice-born one, having heard of the fall of the old son of Shantanu, of Balhika, of Drona, of Somadatta, of Bhurisravas, as well as of other friends, of his sons and grandsons, the king did not give up his life; so, I suppose, that to yield up one's life is, O regenerate person, highly difficult.