Musnad Ahmad 616
It was narrated that Suwaid bin Ghafalah said:
`Ali (رضي الله عنه) said: When I narrate to you from the Messenger of Allah (ﷺ), it would be dearer to me to be thrown down from the sky than to tell lies about him. But if I narrate to you from anyone else, then I am a warrior and war is deceit. I heard the Messenger of Allah (ﷺ) say: `There will emerge at the end of time people who are young in age and immature. They will speak like the best of people but their faith will go no deeper than their throats. Wherever you encounter them, kill them, for killing them brings to the one who kills them reward with Allah on the Day of Resurrection.`
حَدَّثَنَا أَبُو مُعَاوِيَةَ، حَدَّثَنَا الْأَعْمَشُ، عَنْ خَيْثَمَةَ، عَنْ سُوَيْدِ بْنِ غَفَلَةَ، قَالَ قَالَ عَلِيٌّ رَضِيَ اللَّهُ عَنْهُ إِذَا حَدَّثْتُكُمْ عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ حَدِيثًا فَلَأَنْ أَخِرَّ مِنْ السَّمَاءِ أَحَبُّ إِلَيَّ مِنْ أَنْ أَكْذِبَ عَلَيْهِ وَإِذَا حَدَّثْتُكُمْ عَنْ غَيْرِهِ فَإِنَّمَا أَنَا رَجُلٌ مُحَارِبٌ وَالْحَرْبُ خَدْعَةٌ سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ يَخْرُجُ فِي آخِرِ الزَّمَانِ أَقْوَامٌ أَحْدَاثُ الْأَسْنَانِ سُفَهَاءُ الْأَحْلَامِ يَقُولُونَ مِنْ قَوْلِ خَيْرِ الْبَرِيَّةِ لَا يُجَاوِزُ إِيمَانُهُمْ حَنَاجِرَهُمْ فَأَيْنَمَا لَقِيتُمُوهُمْ فَاقْتُلُوهُمْ فَإِنَّ قَتْلَهُمْ أَجْرٌ لِمَنْ قَتَلَهُمْ يَوْمَ الْقِيَامَةِ‏.‏