Sahih Muslim Book 4, Hadith Number 1815.

Chapter : How Amr b. Abasa embraced Islam.

Kuraib, the freed slave of Ibn ‘Abbas, reported that ‘Abdullah b. ‘Abbas, ‘Abd al-Rahman b. Azhar, al-Miswar b. Makhrama sent him to ‘Aisha, the wife of the Messenger of Allah (may peace be upon him), telling him to give her their greetings, and ask her about the two rak’ahs after the afternoon prayer, (for) “we have heard that you observe them whereas it has been conveyed to us that the Messenger of Allah (may peace be upon him) prohibited their observance.” Ibn ‘Abbas said: I along with ‘Umar b. al-Khattab dissuaded people to do so (to observe two rak’ahs of prayer). Kuraib said: I went to her (‘Aisha) and conveyed to her the message with which I was sent. She said: (Better) ask Umm Salama. So I went to them (those who had sent him to Hadrat ‘Aisha) and informed them about what she had said. They sent me back to Umm Salama with that with which I was sent to ‘Aisha. Umm Salama said: I beard the Messenger of Allah (may peace be upon him) prohibiting them, and then afterwards I saw him observing them. And when he observed them (two rak’ahs) he had already observed the ‘Asr prayer. Then he (the Holy Prophet) came, while there were with me ladies of Banu Haram, a tribe of the Ansar and he (the Holy Prophet) observed them (the two rak’ahs). I sent a slave-girl to him asking her to stand by his side and say to him that Umm Salama says: Messenger of Allah, I heard you prohibiting these two rak’ahs, whereas I saw you observing them; and if he (the Holy Prophet) points with his hand (to wait), then do wait. The slave-girl did like that. He (the Holy Prophet) pointed out with his hand and she got aside and waited, and when he had finished (the prayer) he said: Daughter of Abu Umayya. you have asked about the two rak’ahs after the ‘Asr prayer. Some people of ‘Abu al-Qais came to me for embracing Islam and hindered me from observing the two rak’ahs which come after the noon prayer. So those are the two I have been praying.