Jamadagni was certainly very powerful due to his austerities, but because of a slight offense by his poor wife, Renuka, he ordered that she be killed. This certainly was a sinful act, and therefore Jamadagni was killed by the sons of Kartaviryarjuna, as described herein. Lord Parasurama was also infected by sin because of killing Kartaviryarjuna, although this was not very offensive. Therefore, whether one be Kartaviryarjuna, Lord Parasurama, Jamadagni or whoever one may be, one must act very cautiously and sagaciously; otherwise one must suffer the results of sinful activities. This is the lesson we receive from Vedic literature.