He married Renuka, the daughter of king Prasenajit, who was contented to partake in his ascetic life. Once Renuka 'went to bathe in the river, she saw Chitraratha, the prince of Mrittikavati, sporting with his wife in the water. She felt envious of their enjoyment and retumed to the hermitage with defiled thoughts. Perceiving her agitation, her husband Jamadagni was exceedingly wrath. He commanded his sons to kili their mother.
It was only Parashurama, -who obeyed his order and with his axe struck off his mother's head. For this service, Parashurama received the boon of invincibility.Once the king Kartavirya came to the hermitage ofJamadagni and in his absence carried off his cow Kamadhenu. Parashurama was also not in the house. When he came to know of it, he followed the king and killed him in the battle.
The sons of the deceased king, in great rage, came to the hermitage and killed the sage Jamadagni. When Parashurama came home and saw his lifeless father, he swore that he would extirpate the whole race of Kshatriyas.In the above reference from Guru Granth Sahib, Raghuvira or Ramachandra is shown as having been victorious over Parashurama the son of Jamadagni. Parashurama was destroying the race of Kshatriyas, when Ramchandra in an encounter with him divested him of his axe. This account is given in Ramayana. See : Parashurama in Das Avatars
1. Kohli, Surindar Singh (ed), Dictionary of Mythological References in Guru Granth Sahib, 1993