virah-the son of King Prthu; ca-also; asvam-the horse; upadaya-taking; pitr-yajnam-to the sacrificial arena of his father; atha-thereafter; avrajat-went; tat-that; avadyam-abominable; hareh-of Indra; rupam-dress; jagrhuh-adopted; jnana-durbalah-those with a poor fund of knowledge.