Sunan an-Nasa'i 4201
It was narrated that Abu Hurairah said " The Messenger of Allah said:
'No ruler is appointed but he has tow groups of advisers: A group which urges him to do good and tells him not to do evil, and a group which does its best to corrupt  him. Whoever is protected from their evil is indeed protected. And he (the ruler) belongs to the group that has the greater influence over him."
أَخْبَرَنَا مُحَمَّدُ بْنُ يَحْيَى بْنِ عَبْدِ اللَّهِ، قَالَ حَدَّثَنَا مُعَمَّرُ بْنُ يَعْمَرَ، قَالَ حَدَّثَنِي مُعَاوِيَةُ بْنُ سَلاَّمٍ، قَالَ حَدَّثَنِي الزُّهْرِيُّ، قَالَ حَدَّثَنِي أَبُو سَلَمَةَ بْنُ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ مَا مِنْ وَالٍ إِلاَّ وَلَهُ بِطَانَتَانِ بِطَانَةٌ تَأْمُرُهُ بِالْمَعْرُوفِ وَتَنْهَاهُ عَنِ الْمُنْكَرِ وَبِطَانَةٌ لاَ تَأْلُوهُ خَبَالاً فَمَنْ وُقِيَ شَرَّهَا فَقَدْ وُقِيَ وَهُوَ مِنَ الَّتِي تَغْلِبُ عَلَيْهِ مِنْهُمَا ‏"‏ ‏.‏