Sahih al-Bukhari 1775, 1776

It is related from Mujahid, "'Urwa ibn az-Zubayr and I entered the mosque and found 'Abdullah ibn 'Umar sitting next to the room of 'A'isha. Some other people were praying the Duha prayer in the mosque." Mujahid said, "We asked him [Ibn 'Umar] about their prayer and he said, 'It is an innovation.' Then he ['Urwa] said to him, 'How many times did the Prophet, may Allah bless him and grant him peace, do 'umra?' He said, 'Four times: once in Rajab.' We did not like to contradict him." He said, "We heard 'A'isha, Umm al-Mu'minin, cleaning her teeth in the room and so 'Urwa said, 'O mother! O Umm al-Mu'minin! Do you not hear what Abu 'Abdu'r-Rahman is saying?' She said, 'What is he saying?' He said, 'He says that the Messenger of Allah, may Allah bless him and grant him peace, went on 'umra four times, one of which was in Rajab.' She said, 'May Allah have mercy on Abu 'Abdu'r-Rahman. He did not do any 'umra but that he was present with him. He never went on 'umra in Rajab.'"