If a judge issues a ruling, having tried his best to decide correctly, and his ruling is right, he will have a double reward, but if he issues a ruling, having tried his best to decide correctly, and his ruling is wrong, he will have a single reward
‘Amr ibn al-‘Ās (may Allah be pleased with him) reported: The Messenger of Allah (may Allah’s peace and blessings be upon him) said: "If a judge issues a ruling, having tried his best to decide correctly, and his ruling is right, he will have a double reward, but if he…