tad-raktena nadim ghoram
hetum krtva pitr-vadham
krtva nihksatriyam prabhuh
sonitodan hradan nava
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
With the blood of the bodies of these sons, Lord Parasurama created a ghastly river, which brought great fear to the kings who had no respect for brahminical culture. Because the ksatriyas, the men of power in government, were performing sinful activities, Lord Parasurama, on the plea of retaliating for the murder of his father, rid all the ksatriyas from the face of the earth twenty-one times. Indeed, in the place known as Samanta-pañcaka he created nine lakes filled with their blood.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Parasurama is the Supreme Personality of Godhead, and his eternal mission is paritranaya sadhunam vinasaya ca duskrtam — to protect the devotees and annihilate the miscreants. To kill all the sinful men is one among the tasks of the incarnation of Godhead. Lord Parasurama killed all the ksatriyas twenty-one times consecutively because they were disobedient to the brahminical culture. That the ksatriyas had killed his father was only a plea; the real fact is that because the ksatriyas, the ruling class, had become polluted, their position was inauspicious. Brahminical culture is enjoined in the sastra, especially in Bhagavad-gita (catur-varnyam maya srstam guna-karma-vibhagasah). According to the laws of nature, whether at the time of Parasurama or at the present, if the government becomes irresponsible and sinful, not caring for brahminical culture, there will certainly be an incarnation of God like Parasurama to create a devastation by fire, famine, pestilence or some other calamity. Whenever the government disrespects the supremacy of the Personality of Godhead and fails to protect the institution of varnasrama-dharma, it will certainly have to face such catastrophes as formerly brought about by Lord Parasurama.