If the people witness an oppressor and they do not take him by his hands (to prevent him) then they are close to Allah covering them all with punishment
Not preventing the oppressors is a cause for collective punishment from Allah
إِنَّ النَّاسَ إِذَا رَأَوُا الظَّالِمَ فَلَمْ يَأْخُذُوا عَلَى يَدَيْهِ أَوْشَكَ أَنْ يَعُمَّهُمُ اللَّهُ بِعِقَابٍ
If the people witness an oppressor and they do not take him by his hands (to prevent him) then they are close to Allah covering them all with punishment
(Abu Dawud, Tirmidhi, ibn Maja)
Commentary
a. Abu Bakr as-Siddiq (ra) said “O people, you read this verse of the Book of Allah and you apply it in a way Allah did not intend it, “O you who believe, take care of your ownselves. If you follow the right guidance no harm can come to you from those who are in error” (TMQ 5:105) and I heard the Messenger of Allah صلى الله عليه وسلم say if some amongst a people act upon sins or without right, and the people do not change it, then they are close to Allah covering them all with punishment”
b. These narrations indicate the consequences of neglecting preventing the oppressor from their oppression, since oppression ultimately will affect the whole society as detailed in the narration of the ship.
c. Imam Ibn Qayyim said: “The Shaitan has misled most people by beautifying for them the performance of certain voluntary acts of worship such as voluntary prayers and voluntary fasting while neglecting other obligatory acts of worship such as enjoining the good and eradicating the evil, to the extent that they do not even make the intention of performing them….For the essence of our religion is to perform what Allah سبحانه وتعالى ordered us to do.
The one who does not perform his obligations is actually worse than the one who performs sins. Anyone having some knowledge about the revelation of Allah, the guidance of the Prophet and the life of the companions would see that those who are pointed at today as the most pious people are in fact the least pious… Indeed, what deen and what good is there in a person who witnesses the sanctities of Allah سبحانه وتعالى being violated, His Hudood not applied, His religion abandoned, the Sunnah of His Messenger shunned, and yet remains still with a cold heart and a silent tongue – a dumb Shaitan. In the same way the one who talks falsehood is a speaking Shaitan. Isn’t the misfortune of Islam due only to those who whenever their food and positions are secure, would not care about what happens to the religion? The best among them would offer a sorry face. But if there was a shortcoming in one of the things their heart is attached to like their rank or money, they would sacrifice and strive and strain and struggle and use the three levels of prevention (their hands, tongues and hearts, as mentioned in hadith 49) according to their capability. These people, besides deserving the anger of Allah, are afflicted with the greatest calamity without even knowing it: They have a dead heart. Indeed the more alive a person’s heart is, the stronger its anger for the sake of Allah and the more complete his support to Islam and Muslims”