Musnad Ahmad 1153:1488

'Ali ibn 'Asim narrated to us, he said: Hanzalah al-Sadusi informed us, from 'Abdullah ibn al-Harith ibn Nawfal, who said: Mu'awiyah prayed 'Asr with the people, then he turned and saw people praying after 'Asr. He entered, and Ibn 'Abbas entered with him, and I was with him. Mu'awiyah made space for him on the couch, and he sat with him. He said: "What is this prayer that I saw the people praying, which I did not see the Prophet, may Allah bless him and grant him peace, pray, nor did he command it?" He said: "That is what Ibn al-Zubayr is giving them fatwa for." Ibn al-Zubayr entered, greeted, and sat down. Mu'awiyah said: "O Ibn al-Zubayr, what is this prayer that you command the people to pray, which we did not see the Messenger of Allah, may Allah bless him and grant him peace, pray, nor did he command it?" He said: "'A'ishah, the Mother of the Believers, told me that the Messenger of Allah, may Allah bless him and grant him peace, prayed it with her in her house." He said: So Mu'awiyah commanded me and another man to go to 'A'ishah and ask her about that. He said: So I entered upon her and asked her about that, and I informed her of what Ibn al-Zubayr had reported from her. She said: "Ibn al-Zubayr did not remember correctly. I only told him that the Messenger of Allah, may Allah bless him and grant him peace, prayed these two rak'ahs after 'Asr at my place. I asked him, and I said: 'You prayed two rak'ahs that you did not use to pray?' He said: 'Something came to me, and I was occupied with its distribution, so I missed the two rak'ahs after Dhuhr. Then Bilal came to me and called me to prayer, and I disliked keeping the people waiting, so I prayed them [now].'" He said: So I returned and informed Mu'awiyah. He said: Ibn al-Zubayr said: "Did he not pray them? We will not abandon them." Mu'awiyah said to him: "You will always be in opposition."