The Arabic word Indhār means to warn or admonish someone of a future danger. The Holy Qur’ān has frequently used this word to refer to the basic duty of Prophets and Messengers of Allah to warn their addressees regarding the Hereafter. Indhār can be classified in two major categories according to the person who discharges this responsibility.

I. Indhār of the Prophets (Anbiyā) and Messengers (Rusul)

All the Prophets and Messengers of God try to substantiate the happening of the Day of Judgment. The following verses clearly point out that it is the basic target of the admonition of the Prophets:

كَانَ النَّاسُ أُمَّةً وَاحِدَةً فَبَعَثَ اللّهُ النَّبِيِّينَ مُبَشِّرِينَ وَمُنذِرِينَ (٢١٣:٢)

Mankind were one community, and Allah sent (unto them) Prophets as bearers of good tidings and as warners. (2:213)

يَا مَعْشَرَ الْجِنِّ وَالإِنسِ أَلَمْ يَأْتِكُمْ رُسُلٌ مِّنكُمْ يَقُصُّونَ عَلَيْكُمْ آيَاتِي وَيُنذِرُونَكُمْ لِقَاء يَوْمِكُمْ هذا (١٣٠:٦)

O ye assembly of the jinn and humankind! Came there not to you messengers of your own who recounted to you My tokens and warned you of the meeting of this Day of yours? (6:130)

َأَنذِرْ بِهِ الَّذِينَ يَخَافُونَ أَن يُحْشَرُواْ إِلَى رَبِّهِمْ لَيْسَ لَهُم مِّن دُونِهِ وَلِيٌّ وَلاَ شَفِيعٌ لَّعَلَّهُمْ يَتَّقُونَ (٥١:٦)

Warn thereby those who fear [because they know] that they will be gathered unto their Lord, for whom there is no protecting friend nor intercessor beside Him, that they may ward off (evil). (6:51)

وَأَنذِرْهُمْ يَوْمَ الْحَسْرَةِ إِذْ قُضِيَ الْأَمْرُ وَهُمْ فِي غَفْلَةٍ وَهُمْ لَا يُؤْمِنُونَ (٣٩:١٩)

And warn them of the Day of anguish when the case hath been decided. Now they are in a state of carelessness, and they believe not. (19:39)

Some of the prophets were also appointed as Rusul. Rusul in fact are sent as symbols of the final judgment which will take place in the Hereafter. A Rasūl, in contrast to a Nābī (Prophet) does not only warn his addressees of the Hereafter but warns them of the punishment in this very world if they reject his message. The Almighty has adopted this principle to deal with the rejecters of the Rasūl. In this regard the Holy Qur’ān says:

إِنَّ الَّذِينَ يُحَادُّونَ اللَّهَ وَرَسُولَهُ أُوْلَئِكَ فِي الأَذَلِّينَ كَتَبَ اللَّهُ لَأَغْلِبَنَّ أَنَا وَرُسُلِي إِنَّ اللَّهَ قَوِيٌّ عَزِيزٌ (٥٨ :٢٠-١)

Those who oppose God and His Messengers shall be brought low. God has decreed: I will surely triumph, Myself and My Messengers. God is most powerful, Mighty. (58:20-21)

The following verses of the Holy Qur’ān refer to the history of the Messengers of the past to provide the historical testimony to substantiate the fact that the rejecters of Messengers have to face the punishment of their crime in this very world.

فَكَذَّبُوهُ فَنَجَّيْنَاهُ وَمَن مَّعَهُ فِي الْفُلْكِ وَجَعَلْنَاهُمْ خَلاَئِفَ وَأَغْرَقْنَا الَّذِينَ كَذَّبُواْ بِآيَاتِنَا فَانظُرْ كَيْفَ كَانَ عَاقِبَةُ الْمُنذَرِينَ (٧٣:١٠)

But they denied him, so We saved him and those with him in the ship, and made them viceroys [in the earth], while We drowned those who denied Our revelations. See then the nature of the consequence for those who had been warned. (10:73)

فَإِنْ أَعْرَضُوا فَقُلْ أَنذَرْتُكُمْ صَاعِقَةً مِّثْلَ صَاعِقَةِ عَادٍ وَثَمُودَ (١٣:٤١)

But if they turn away, then say: I warn you of a thunderbolt like the thunderbolt (which fell of old upon the tribes) of `Ād and Thamūd. (41:13)

The Holy Qur’ān frequently narrates the history of the nations of the past who rejected their respective Rusul and were destined to doom in this world. Sūrah Qamar summarizes stories of different Messengers of the past and each narration is concluded with remarks ‘Then see how [dreadful] was My punishment after My warnings!’. This remark serves as a reminder for the Quraysh to take lesson from the episodes of the previous Rusul and realize the severity of the matter. The effect of the Indhār of the Rasūl extends to his companions who are in fact the representatives of the respective Rasūl and are always bestowed with the success in this world and their opponents are sure to be defeated.

II. Indhār of Religious Scholars

The Holy Qur’ān has also attributed Indhār to scholars who have special insight in religion. The Holy Qur’ān says:

وَمَا كَانَ الْمُؤْمِنُونَ لِيَنفِرُواْ كَآفَّةً فَلَوْلاَ نَفَرَ مِن كُلِّ فِرْقَةٍ مِّنْهُمْ طَآئِفَةٌ لِّيَتَفَقَّهُواْ فِي الدِّينِ وَلِيُنذِرُواْ قَوْمَهُمْ إِذَا رَجَعُواْ إِلَيْهِمْ لَعَلَّهُمْ يَحْذَرُونَ (١٢٢:٩)

And it was not possible that all the believers undertake the task – then why did not a few from every group got up to gain sound knowledge in religion, and warn their people when they would return to them so that they may save themselves [from the punishment of the Hereafter]. (9:122)

The verse clearly indicates the fact that it is not possible and therefore not incumbent upon every Muslim to acquire in-depth knowledge of the religious sources. It recommends that some of them should come out to acquire the knowledge and then return to their folks and admonish them.