The institution of Amr bil-Ma’ruf and Nahi ‘anil-Munkar (commanding virtue and forbidding vice) is very important in Islam and mentioned throughout the Suhuf-e-Mutahhara (Quraan) as an integral characteristic of true Believers. This practice is the birthright of every Muslim, whether in a position of authority or not. But its manifestation among those Muslims not in a position of political or administrative authority is restricted to being non-violent. Here by non-violent I mean short of shedding blood or causing serious injury. The Prophet Muhammad ﷺ said:
مَنْ رَأَى مِنْكُمْ مُنْكَرًا فَلْيُغَيِّرْهُ بِيَدِهِ فَإِنْ لَمْ يَسْتَطِعْ فَبِلِسَانِهِ فَإِنْ لَمْ يَسْتَطِعْ فَبِقَلْبِهِ وَذَلِكَ أَضْعَفُ الإِيمَانِ
Whosoever of you sees an evil, let him change it with his hand; and if he is not able to do so, then [let him change it] with his tongue; and if he is not able to do so, then with his heart - and that is the weakest of faith.
This Hadith proves that forbidding vice with one’s own hand is not the sole prerogative of the State, but every Muslim is authorized to do so if he is able. The only qualification is that this dispensation for vigilantism has to be non-violent, and as I have already mentioned, non-violence means short of actual bloodshed or causing serious injury. A perfect example of this is the Nass which delegates authority to a husband to physically strike his wife guilty of ill-conduct (Sura 4: 34). So for example, if a group of Muslims, armed with sticks, use rough force to break up a sinful music concert or close down a shop selling liqor, etc., they do not require prior authorization from the State since they have already been authorized to do so by Allah Himself in the Holy Quraan, i.e., the institution of Amr bil-Ma’ruf and Nahi ‘anil-Munkar. But keep in mind that this is the extent of vigilantism allowed in Islam; for otherwise only the State is authorized to implement the Hudud of the penal code of the Shari’a and to execute those deserving of capital punishment through the sword or by means of crucifixion.
However, one should beware that the institution of Amr bil-Ma’ruf and Nahi ‘anil-Munkar can and does become suspended depending on external circumstances. This is based on the Prophetic Hadith:
بَلِ ائْتَمِرُوا بِالْمَعْرُوفِ وَتَنَاهَوْا عَنِ الْمُنْكَرِ حَتَّى إِذَا رَأَيْتَ شُحًّا مُطَاعًا وَهَوًى مُتَّبَعًا وَدُنْيَا مُؤْثَرَةً وَإِعْجَابَ كُلِّ ذِي رَأْىٍ بِرَأْيِهِ وَرَأَيْتَ أَمْرًا لاَ يَدَانِ لَكَ بِهِ فَعَلَيْكَ خُوَيْصَّةَ نَفْسِكَ وَدَعْ أَمْرَ الْعَوَامِّ فَإِنَّ مِنْ وَرَائِكُمْ أَيَّامَ الصَّبْرِ الصَّبْرُ فِيهِنَّ مِثْلُ قَبْضٍ عَلَى الْجَمْرِ لِلْعَامِلِ فِيهِنَّ مِثْلُ أَجْرِ خَمْسِينَ رَجُلاً يَعْمَلُونَ بِمِثْلِ عَمَلِهِ
“Enjoin good upon one another and forbid one another to do evil, but if you see overwhelming stinginess, desires being followed, this world being preferred (to the Hereafter), every person with an opinion feeling proud of it, and you realize that you have no power to deal with it, then you have to mind your own business and leave the common folk to their own devices. After you will come days of patience, during which patience will be like grasping a burning ember, and one who does good deeds will have a reward like that of fifty men doing the same deed.”
قِيلَ يَا رَسُولَ اللَّهِ مَتَى نَتْرُكُ الأَمْرَ بِالْمَعْرُوفِ وَالنَّهْىَ عَنِ الْمُنْكَرِ قَالَ إِذَا ظَهَرَ فِيكُمْ مَا ظَهَرَ فِي الأُمَمِ قَبْلَكُمْ قُلْنَا يَا رَسُولَ اللَّهِ وَمَا ظَهَرَ فِي الأُمَمِ قَبْلَنَا قَالَ الْمُلْكُ فِي صِغَارِكُمْ وَالْفَاحِشَةُ فِي كِبَارِكُمْ وَالْعِلْمُ فِي رُذَالَتِكُمْ قَالَ زَيْدٌ تَفْسِيرُ مَعْنَى قَوْلِ النَّبِيِّ ـ صلى الله عليه وسلم ـ وَالْعِلْمُ فِي رُذَالَتِكُمْ . إِذَا كَانَ الْعِلْمُ فِي الْفُسَّاقِ
It was said: “O Messenger of Allah, when should we stop enjoining what is good and forbidding what is evil?” He said: “When there appears among you that which appeared among those who came before you.” We said: “O Messenger of Allah, what appeared among those that came before us?” He said: “Kingship given to your youth, immorality even among the old, and knowledge among the base and vile.” (Sunan Ibn Maja; Kitab al-Fitan)