Riyad as-Salihin, Book 19, Hadith 1856 (In-Book) ⓘ
'Amr bin 'Al-'As (May Allah be pleased with him) said: I heard the Messenger of Allah saying, "When a judge utilizes his skill of judgement and comes to a right decision, he will have a double reward, but when he uses his judgement and commits a mistake, he will have a single reward."[Al-Bukhari and Muslim]
وعن عمرو بن العاص رضي الله عنه سمع رسول الله صلى الله عليه وسلم يقول: "إذا حكم الحاكم، فاجتهد، ثم أصاب، فله أجران، وإن حكم واجتهد، فأخطأ، فله أجر" ((متفق عليه)).