(18) The Offices of Commander and Qadi
كتاب الإمارة والقضاء
(2a) Chapter: How to Conduct the Office of Qadi, and Fear of it - Section 1
(2) باب العمل في القضاء والخوف منه - الفصل الأول
Mishkat al-Masabih 3732 
‘Abdallah b. ‘Amr and Abu Huraira reportad God’s Messenger as saying, “When a judge gives a decision having tried his best to decide correctly and is right, he will have a double reward; and when he gives a decision having tried his best to decide correctly and is wrong, he will have a single reward.” (Bukhari and Muslim.)
وَعَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو وَأَبِي هُرَيْرَةَ قَالَا: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا حَكَمَ الْحَاكِمُ فَاجْتَهَدَ فَأَصَابَ فَلَهُ أَجْرَانِ وَإِذَا حَكَمَ فَاجْتَهَدَ فَأَخْطَأَ فلهُ أجرٌ واحدٌ»
 مُتَّفَقٌ عَلَيْهِ  (الألباني)حكم :
Reference : Mishkat al-Masabih 3732
In-book reference : Book 18, Hadith 71