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?'"