Musnad Ahmad 1156:89

Muhammad ibn Abd Allah Abu Ahmad al-Zubayri narrated to us, he said: Ubayd Allah ibn Abd Allah ibn Mawhab narrated to us, he said: My paternal uncle—meaning Ubayd Allah ibn Abd Allah ibn Mawhab—narrated to me, he said: Abu Bakr ibn Abd al-Rahman ibn al-Harith ibn Hisham narrated to me, he said: My father resolved to perform Umrah. When the time for his departure arrived, he said: "O my son, if we were to enter upon the Amir and bid him farewell." I said: "As you wish." He said: So we entered upon Marwan, and with him were a group of people, among them Abd Allah ibn al-Zubayr. They mentioned the two rak'ahs that Ibn al-Zubayr prays after the Asr prayer. Marwan said to him: "From whom did you take them, O Ibn al-Zubayr?" He said: "Abu Hurayrah informed me of them, from Aisha." Marwan sent [a messenger] to Aisha: "What are the two rak'ahs that Ibn al-Zubayr mentions, that Abu Hurayrah informed him from you that the Messenger of Allah, peace and blessings of Allah be upon him, used to pray them after Asr?" She sent back to him: "Umm Salamah informed me of them." He sent [a messenger] to Umm Salamah: "What are the two rak'ahs that Aisha claims you informed her that the Messenger of Allah, peace and blessings of Allah be upon him, used to pray them after Asr?" She said: "May Allah forgive Aisha, she has placed my matter in the wrong place. The Messenger of Allah, peace and blessings of Allah be upon him, prayed Dhuhr, and wealth was brought to him, so he sat distributing it until the mu'adhdhin came to him for Asr. He prayed Asr, then he turned to me—and it was my day—so he prayed two light rak'ahs. I said: 'What are these two rak'ahs, O Messenger of Allah? Were you commanded to do them?' He said: 'No, but they are two rak'ahs I used to pray after Dhuhr, but the distribution of this wealth occupied me until the mu'adhdhin came to me for Asr, and I disliked leaving them.'" Ibn al-Zubayr said: "Allahu Akbar! Did he not pray them once? By Allah, I will never leave them." And Umm Salamah said: "I never saw him pray them before that, nor after it."