Sunan Ibn Majah 218
It was narrated that Nafi' bin 'Abdul-Harith met 'Umar bin Khattab in 'Usfan, when 'Umar had appointed him as his governer in Makkah.:
'Umar asked: "Whom have you appointed as your deputy over the people of the valley?" He said: "I have appointed Ibn Abza over them." 'Umar said: "Who is Ibn Abza?" Nafi' said: "One of our freed slaves." 'Umar said: "Have you appointed a freed slave over them?" Nafi' said: "He has great knowledge of the Book of Allah, is well versed in the rules of inheritance (Fara'id) and is a (good) judge." 'Umar said: "Did not your prophet say: 'Allah raises some people (in status) because of this book and brings others low because of it?'"
حَدَّثَنَا أَبُو مَرْوَانَ، مُحَمَّدُ بْنُ عُثْمَانَ الْعُثْمَانِيُّ حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عَامِرِ بْنِ وَاثِلَةَ أَبِي الطُّفَيْلِ، أَنَّ نَافِعَ بْنَ عَبْدِ الْحَارِثِ، لَقِيَ عُمَرَ بْنَ الْخَطَّابِ بِعُسْفَانَ - وَكَانَ عُمَرُ اسْتَعْمَلَهُ عَلَى مَكَّةَ - فَقَالَ عُمَرُ مَنِ اسْتَخْلَفْتَ عَلَى أَهْلِ الْوَادِي قَالَ اسْتَخْلَفْتُ عَلَيْهِمُ ابْنَ أَبْزَى ‏.‏ قَالَ وَمَنِ ابْنُ أَبْزَى قَالَ رَجُلٌ مِنْ مَوَالِينَا ‏.‏ قَالَ عُمَرُ فَاسْتَخْلَفْتَ عَلَيْهِمْ مَوْلًى قَالَ إِنَّهُ قَارِئٌ لِكِتَابِ اللَّهِ تَعَالَى عَالِمٌ بِالْفَرَائِضِ قَاضٍ ‏.‏ قَالَ عُمَرُ أَمَا إِنَّ نَبِيَّكُمْ ـ صلى الله عليه وسلم ـ قَالَ ‏
"‏ إِنَّ اللَّهَ يَرْفَعُ بِهَذَا الْكِتَابِ أَقْوَامًا وَيَضَعُ بِهِ آخَرِينَ ‏"‏ ‏.‏