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

Expressions researched:
"Because the kṣatriyas, the men of power in government, were performing sinful activities, Lord Paraśurāma, on the plea of retaliating for the murder of his father, rid all the kṣatriyas from the face of the earth twenty-one times"

Srimad-Bhagavatam

SB Canto 9

With the blood of the bodies of these sons, Lord Paraśurāma created a ghastly river, which brought great fear to the kings who had no respect for brahminical culture. Because the kṣatriyas, the men of power in government, were performing sinful activities, Lord Paraśurāma, on the plea of retaliating for the murder of his father, rid all the kṣatriyas 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.

SB 9.16.18-19, Translation and Purport

With the blood of the bodies of these sons, Lord Paraśurāma created a ghastly river, which brought great fear to the kings who had no respect for brahminical culture. Because the kṣatriyas, the men of power in government, were performing sinful activities, Lord Paraśurāma, on the plea of retaliating for the murder of his father, rid all the kṣatriyas 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.

Paraśurāma is the Supreme Personality of Godhead, and his eternal mission is paritrāṇāya sādhūnāṁ vināśāya ca duṣkṛtām (BG 4.8) — 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 Paraśurāma killed all the kṣatriyas twenty-one times consecutively because they were disobedient to the brahminical culture. That the kṣatriyas had killed his father was only a plea; the real fact is that because the kṣatriyas, the ruling class, had become polluted, their position was inauspicious. Brahminical culture is enjoined in the śāstra, especially in Bhagavad-gītā (cātur-varṇyaṁ mayā sṛṣṭaṁ guṇa-karma-vibhāgaśaḥ (BG 4.13)). According to the laws of nature, whether at the time of Paraśurāma 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 Paraśurāma 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 varṇāśrama-dharma, it will certainly have to face such catastrophes as formerly brought about by Lord Paraśurāma.