Riyad as-Salihin

'Amr bin 'Al-'As (May Allah be pleased with him) said: I heard the Messenger of Allah (ﷺ) 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]