Sahih Muslim Book 007, Hadith Number 2882.
Chapter : Concerning the Umras performed by Allah's Apostle (may peace be upon him) and their respective times.
'Ataa reported that 'Urwa b. Zubair (Allah be pleased with him) had informed him (this): I and Ibn 'Umar were reclining against the (wall) of the apartment of 'Aisha and we were listening to the sound produced by the brushing of her teeth. I said Abu Abd al-Rahman (the kunya of 'Abdullah b. Umar), did Allah's Apostle (may peace be upon him) perform 'Umra in the month of Rijab? He said: Yes. I said to 'Aisha: Mother, are you listening to what Abu Abd al-Rabman is saying? She said: What is he Saying? I said: He is saying that Allah's Apostle (may peace be upon him) performed 'Umra during the month of Rajab, whereupon she said: May Allah grant pardon to Abu Abd al-Rahman I By my life he (the Holy Prophet) did not perform 'Umra during the month of Rajab. And never was there an Umra performed by him (the Holy Prophet) in which he ('Abdullah b. 'Umar) did not join him. Ibn 'Umar heard this and said nothing to affirm It or to deny it, but kept quiet.