Sayyiduna Ali (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) sent me as a judge and instructed: "When two parties come to you, do not pass judgment after hearing only one side, but listen to both sides; you will see how you are to judge."
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 1280
Hadith Gradingحکم دارالسلام:حسن لغيره، وهذا اسناد ضعيف لضعف شريك و حنش