Sahih Bukhari Volume 4, Book 61, Hadith 3497

وَالنَّاسُ مَعَادِنُ : خِيَارُهُمْ فِى الْجَاهِلِيَّةِ خِيَارُهُمْ فِى الْاِسْلَامِ إِذَا فَقِهُوا، تَجِدُوْنَ مِنْ خَيْرِ النَّاسِ أَشَدَّهُم كَرَاهِيَةً لِهَذَا الشَّأنِ حَتَّى يَقَعَ فِيْهِ

People are of different natures: The best amongst them in the Pre-Islamic period are the best in Islam provided they comprehend the religious knowledge. You will find that the best amongst the people in this respect (i.e. of ruling) is he who hates it (i.e. the idea of ruling) most, till he is given the pledge of allegiance."