I heard the Prophet ﷺ saying, "Allah will not deprive you of knowledge after he has given it to you, but it will be taken away through the death of the religious learned men with their knowledge. Then there will remain ignorant people who, when consulted, will give verdicts according to their opinions whereby they will mislead others and go astray."  

سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ إِنَّ اللَّهَ لاَ يَنْزِعُ الْعِلْمَ بَعْدَ أَنْ أَعْطَاهُمُوهُ انْتِزَاعًا وَلَكِنْ يَنْتَزِعُهُ مِنْهُمْ مَعَ قَبْضِ الْعُلَمَاءِ بِعِلْمِهِمْ فَيَبْقَى نَاسٌ جُهَّالٌ يُسْتَفْتَوْنَ فَيُفْتُونَ بِرَأْيِهِمْ فَيُضِلُّونَ وَيَضِلُّونَ فَحَدَّثْتُ عَائِشَةَ زَوْجَ النَّبِيِّ ﷺ ثُمَّ إِنَّ عَبْدَ اللَّهِ بْنَ عَمْرٍو حَجَّ بَعْدُ فَقَالَتْ يَا ابْنَ أُخْتِي انْطَلِقْ إِلَى عَبْدِ اللَّهِ فَاسْتَثْبِتْ لِي مِنْهُ الَّذِي حَدَّثْتَنِي عَنْهُ فَجِئْتُهُ فَسَأَلْتُهُ فَحَدَّثَنِي بِهِ كَنَحْوِ مَا حَدَّثَنِي فَأَتَيْتُ عَائِشَةَ فَأَخْبَرْتُهَا فَعَجِبَتْ فَقَالَتْ وَاللَّهِ لَقَدْ حَفِظَ عَبْدُ اللَّهِ بْنُ عَمْرٍو  

I asked Abu Wail, "Did you witness the battle of Siffin between ʿAli and Muawiya?" He said, "Yes," and added, "Then I heard Sahl bin Hunaif saying, 'O people! Blame your personal opinions in your religion. No doubt, I remember myself on the day of Abi Jandal; if I had the power to refuse the order of Messenger of Allah ﷺ, I would have refused it. We have never put our swords on our shoulders to get involved in a situation that might have been horrible for us, but those swords brought us to victory and peace, except this present situation.' " Abu Wail said, "I witnessed the battle of Siffin, and how nasty Siffin was!"  

سَأَلْتُ أَبَا وَائِلٍ هَلْ شَهِدْتَ صِفِّينَ قَالَ نَعَمْ فَسَمِعْتُ سَهْلَ بْنَ حُنَيْفٍ يَقُولُ ح وَحَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ حَدَّثَنَا أَبُو عَوَانَةَ عَنِ الأَعْمَشِ عَنْ أَبِي وَائِلٍ قَالَ قَالَ سَهْلُ بْنُ حُنَيْفٍ يَا أَيُّهَا النَّاسُ اتَّهِمُوا رَأْيَكُمْ عَلَى دِينِكُمْ لَقَدْ رَأَيْتُنِي يَوْمَ أَبِي جَنْدَلٍ وَلَوْ أَسْتَطِيعُ أَنَّ أَرُدَّ أَمْرَ رَسُولِ اللَّهِ ﷺ لَرَدَدْتُهُ وَمَا وَضَعْنَا سُيُوفَنَا عَلَى عَوَاتِقِنَا إِلَى أَمْرٍ يُفْظِعُنَا إِلاَّ أَسْهَلْنَ بِنَا إِلَى أَمْرٍ نَعْرِفُهُ غَيْرَ هَذَا الأَمْرِ قَالَ وَقَالَ أَبُو وَائِلٍ شَهِدْتُ صِفِّينَ وَبِئْسَتْ صِفُّونَ