Shiavault - a Vault of Shia Islamic Books The Promised Savior: an Inquiry Into the Imamate of Imam Mahdi (a.s) From the Viewpoint of Muslim Thinkers Chapter Two: Imam Mahdi and Mahdviyat in successively reported traditions Every time there has to be an Imam who is acceptable to people and people follow him in every matter, considering him as an authority between themselves and Allah.
رُّسُلاً مُّبَشِّرِينَ وَمُنذِرِينَ لِئَلاَّ يَكُونَ لِلنَّاسِ عَلَى اللّهِ حُجَّةٌ بَعْدَ الرُّسُلِ وَكَانَ اللّهُ عَزِيزًا حَكِيمًا[^23] (We sent) apostles as the givers of good news and as warners, so that people should not have a plea against Allah after the (coming of) apostles; and Allah is Mighty, Wise.
Elsewhere the Holy Quran maintains: إِذْ أَنتُم بِالْعُدْوَةِ الدُّنْيَا وَهُم بِالْعُدْوَةِ الْقُصْوَى وَالرَّكْبُ أَسْفَلَ مِنكُمْ وَلَوْ تَوَاعَدتَّمْ لاَخْتَلَفْتُمْ فِي الْمِيعَادِ وَلَـكِن لِّيَقْضِيَ اللّهُ أَمْراً كَانَ مَفْعُولاً لِّيَهْلِكَ مَنْ هَلَكَ عَن بَيِّنَةٍ وَيَحْيَى مَنْ حَيَّ عَن بَيِّنَةٍ وَإِنَّ اللّهَ لَسَمِيعٌ عَلِيمٌ[^24] When you were on the nearer side (of the valley) and they were on the farthest side, while the caravan was in a lower place than you; and if you had mutually made an appointment, you would certainly have broken away from the appointment, but—in order that Allah might bring about a matter which was to be done, that he who would perish might perish by clear proof, and he who would live might live by clear proof; and most surely Allah is Hearing, Knowing.
Quran again says: سَيَقُولُ الَّذِينَ أَشْرَكُواْ لَوْ شَاء اللّهُ مَا أَشْرَكْنَا وَلاَ آبَاؤُنَا وَلاَ حَرَّمْنَا مِن شَيْءٍ كَذَلِكَ كَذَّبَ الَّذِينَ مِن قَبْلِهِم حَتَّى ذَاقُواْ بَأْسَنَا قُلْ هَلْ عِندَكُم مِّنْ عِلْمٍ فَتُخْرِجُوهُ لَنَا إِن تَتَّبِعُونَ إِلاَّ الظَّنَّ وَإِنْ أَنتُمْ إَلاَّ تَخْرُصُونَ.[^25] Those who are polytheists will say: If Allah had pleased we would not have associated (aught with Him) nor our fathers, nor would we have forbidden (to ourselves) anything; even so did those before them reject until they tasted Our punishment.
Say: Have you any knowledge with you so you should bring it forth to us? You only follow a conjecture and you only tell lies. Referring to reliable prophetic traditions, we come across three successively reported traditions that deal with the issue of imamate. These three traditions prove that there is a perpetual need for an imam and declare that the number of imams does not exceed twelve.