Musnad Ahmad 1153:2320

Ya'qub narrated to us, he said: My father narrated to us, from Ibn Ishaq, he said: Hisham ibn 'Urwah narrated to me, from his father, from 'Aishah, the wife of the Prophet, may Allah bless him and grant him peace, she said: Salma, the freedwoman of the Messenger of Allah, may Allah bless him and grant him peace, or the wife of Abu Rafi', the freedman of the Messenger of Allah, may Allah bless him and grant him peace, came to the Messenger of Allah, may Allah bless him and grant him peace, seeking his permission regarding Abu Rafi', for he had struck her. She said: The Messenger of Allah, may Allah bless him and grant him peace, said to Abu Rafi': "What is the matter between you and her, O Abu Rafi'?" He said: "She annoys me, O Messenger of Allah." The Messenger of Allah, may Allah bless him and grant him peace, said: "How did you annoy him, O Salma?" She said: "O Messenger of Allah, I did not annoy him with anything, but he broke wind while he was praying, so I said to him: 'O Abu Rafi', the Messenger of Allah, may Allah bless him and grant him peace, has commanded the Muslims that if wind exits from one of them, he should perform ablution.' So he stood up and struck me." The Messenger of Allah, may Allah bless him and grant him peace, began to laugh and say: "O Abu Rafi', she only commanded you to do good."