Sahih Muslim Book - 6, Hadith - 1897

وَحَدَّثَنِى زُهَيْرُ بْنُ حَرْبٍ حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ حَدَّثَنِى أَبِى عَنِ ابْنِ شِهَابٍ عَنْ عَامِرِ بْنِ وَاثِلَةَ أَنَّ نَافِعَ بْنَ عَبْدِ الْحَارِثِ لَقِىَ عُمَرَ بِعُسْفَانَ وَكَانَ عُمَرُ يَسْتَعْمِلُهُ عَلَى مَكَّةَ فَقَالَ مَنِ اسْتَعْمَلْتَ عَلَى أَهْلِ الْوَادِى فَقَالَ ابْنَ أَبْزَى. قَالَ وَمَنِ ابْنُ أَبْزَى قَالَ مَوْلًى مِنْ مَوَالِينَا. قَالَ فَاسْتَخْلَفْتَ عَلَيْهِمْ مَوْلًى قَالَ إِنَّهُ قَارِئٌ لِكِتَابِ اللَّهِ عَزَّ وَجَلَّ وَإِنَّهُ عَالِمٌ بِالْفَرَائِضِ. قَالَ عُمَرُ أَمَا إِنَّ نَبِيَّكُمْ -صلى الله عليه وسلم- قَدْ قَالَ « إِنَّ اللَّهَ يَرْفَعُ بِهَذَا الْكِتَابِ أَقْوَامًا وَيَضَعُ بِهِ آخَرِينَ ».

It was narrated from 'Amir bin Wathilah that Nafi' bin 'Abdul-Harith met 'Umar in 'Usfan, and 'Umar had appointed him as governor of Makkah. He said: "Whom did you appoint over the people of the valley?" He said: "Ibn Abza." He said: "Who is Ibn Abza?" He said: "One of our freed slaves." He said: "You have appointed a freed slave over them?!" He said: "He is well versed in the Book of Allah, the Mighty and Sublime, and he is knowledgeable about the Fara'id." 'Umar said: "Your Prophet (s.a.w) said: 'Allah raises some in status because of this Book and He lowers others because of it."'