Srimad Bhagavatam Canto 09, Chapter 16, Text 06

SB 9.16.6

ramah sañcoditah pitra
 bhratrn matra sahavadhit
prabhava-jño muneh samyak
 samadhes tapasas ca sah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Jamadagni then ordered his youngest son, Parasurama, to kill his brothers, who had disobeyed this order, and his mother, who had mentally committed adultery. Lord Parasurama, knowing the power of his father, who was practiced in meditation and austerity, killed his mother and brothers immediately.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The word prabhava-jñah is significant. Parasurama knew the prowess of his father, and therefore he agreed to carry out his father’s order. He thought that if he refused to carry out the order he would be cursed, but if he carried it out his father would be pleased, and when his father was pleased, Parasurama would ask the benediction of having his mother and brothers brought back to life. Parasurama was confident in this regard, and therefore he agreed to kill his mother and brothers.
Srimad Bhagavatam Canto 09, Chapter 16, Text 05
Srimad Bhagavatam Canto 09, Chapter 16, Text 07