Sahih Muslim 2813 c
Jabir reported that Allah's Apostle (may peace be upqn him) said:
The Satan sends detachments of his own in order to put people to trial and the highest in rank, in his eyes, is one who is most notorious in sowing the seed of dissension.
حَدَّثَنِي سَلَمَةُ بْنُ شَبِيبٍ، حَدَّثَنَا الْحَسَنُ بْنُ أَعْيَنَ، حَدَّثَنَا مَعْقِلٌ، عَنْ أَبِي الزُّبَيْرِ، عَنْ 
 جَابِرٍ، أَنَّهُ سَمِعَ النَّبِيَّ صلى الله عليه وسلم يَقُولُ ‏
"‏ يَبْعَثُ الشَّيْطَانُ سَرَايَاهُ فَيَفْتِنُونَ النَّاسَ
 فَأَعْظَمُهُمْ عِنْدَهُ مَنْزِلَةً أَعْظَمُهُمْ فِتْنَةً ‏"‏ ‏.‏