Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with them both) narrates that two disputants brought their case to Sayyiduna Amr bin al-As (may Allah be pleased with him), and he judged between them. The one against whom the judgement was given became displeased and came to the Messenger of Allah (peace and blessings be upon him). Then the Messenger of Allah (peace and blessings be upon him) said: "When a judge judges and exerts himself (ijtihad) and reaches the correct judgement, he has ten rewards; and if he exerts himself and errs, he has two rewards."
Hadith Referenceالمعجم الأوسط / باب الميم / 8988
Hadith Gradingمحدثین:فيه سلمة بن أكسوم، لم يُعرف
Hadith Takhrij«قال الهيثمي: وفيه سلمة بن أكسوم ولم أجد من ترجمه بعلم «مجمع الزوائد ومنبع الفوائد، ج 4، ص 195»» «أخرجه الحاكم فى «المستدرك» برقم: 7096، والدارقطني فى «سننه» برقم: 4457، وأحمد فى «مسنده» برقم: 6870»