Mbh 1.130.4

“And it happened that a soldier in attendance upon king Santanu while the monarch was out a-hunting in the woods, came upon the twins. And seeing the bow and arrows and deer-skin on the ground, he thought they might be the offspring of some Brahmana proficient in the science of arms. Deciding thus, he took up the children along with the bow and arrows, and showed what he had to the king. Beholding them the king was moved with pity, and saying, ‘Let these become my children,’ brought them to his palace. Then that first of men, Santanu, the son of Pratipa having brought Gautama’s twins into his house, performed in respect of them the usual rites of religion. And he began to bring them up and called them Kripa and Kripi, in allusion to the fact that he brought them up from motives of pity (Kripa). The son of Gotama having left his former asylum, continued his study of the science of arms in right earnest. By his spiritual insight he learnt that his son and daughter were in the palace of Santanu. He thereupon went to the monarch and represented everything about his lineage. He then taught Kripa the four branches of the science of arms, and various other branches of knowledge, including all their mysteries and recondite details. In a short time Kripa became an eminent professor of the science (of arms). And the hundred sons of Dhritarashtra, and the Pandavas along with the Yadavas, and the Vrishnis, and many other princes from various lands, began to receive lessons from him in that science.’”