Musnad Ahmad

Once, a woman who had committed adultery was brought before Sayyiduna Umar Farooq (may Allah be pleased with him). After her crime was proven, Sayyiduna Umar (may Allah be pleased with him) ordered her to be stoned. As people were taking her to be stoned, they met Sayyiduna Ali (may Allah be pleased with him) on the way. He inquired about her, and the people informed him that she had committed adultery and Sayyiduna Umar (may Allah be pleased with him) had ordered her to be stoned. Sayyiduna Ali (may Allah be pleased with him) freed the woman from their hands and sent those people back. Those people presented themselves before Sayyiduna Umar (may Allah be pleased with him). He asked, "Why have you returned?" They said, "Sayyiduna Ali (may Allah be pleased with him) sent us back." He said, "Ali (may Allah be pleased with him) would not have done this without reason; he must have some knowledge regarding this matter." So, he sent for Sayyiduna Ali (may Allah be pleased with him). Sayyiduna Ali (may Allah be pleased with him) arrived, appearing somewhat displeased. Sayyiduna Umar (may Allah be pleased with him) asked him the reason for sending the people back. He replied, "Did you not hear the Prophet (peace and blessings be upon him) say: 'Three types of people are exempt from accountability: the sleeping person until he wakes up, the child until he reaches puberty, and the insane person until his sanity returns'?" He said, "Of course." Sayyiduna Ali (may Allah be pleased with him) said, "This woman is insane from such-and-such tribe. It is possible that when the person committed adultery with her, she was not in her senses and was insane." Sayyiduna Umar (may Allah be pleased with him) said, "Brother! I did not know." He said, "Then I do not know either." However, Sayyiduna Umar (may Allah be pleased with him) did not carry out the punishment of stoning upon her after that.