Sahih Muslim Book: 6, Hadith: 1444

وَحَدَّثَنَا مَنْصُورُ بْنُ أَبِي مُزَاحِمٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْمُبَارَكِ، عَنْ أَبِي بَكْرِ بْنِ عُثْمَانَ بْنِ سَهْلِ بْنِ حُنَيْفٍ، قَالَ سَمِعْتُ أَبَا أُمَامَةَ بْنَ سَهْلٍ، يَقُولُ صَلَّيْنَا مَعَ عُمَرَ بْنِ عَبْدِ الْعَزِيزِ الظُّهْرَ ثُمَّ خَرَجْنَا حَتَّى دَخَلْنَا عَلَى أَنَسِ بْنِ مَالِكٍ فَوَجَدْنَاهُ يُصَلِّي الْعَصْرَ فَقُلْتُ يَا عَمِّ مَا هَذِهِ الصَّلاَةُ الَّتِي صَلَّيْتَ قَالَ الْعَصْرُ وَهَذِهِ صَلاَةُ رَسُولِ اللَّهِ صلى الله تعالى عليه وسلم الَّتِي كُنَّا نُصَلِّي مَعَهُ ‏.‏ Abu Umama b. Sahl reported:We offered the noon prayer with Umar b. ‘Abd al-‘Aziz. We then set out till we came to Anas b. Malik and found him busy in saying the afternoon prayer. I said to him: O uncle! which is this prayer that you are offering? He said: It is the afternoon prayer and this is the prayer of the Messenger of Allah (may peace be upon him) that we offered along with him. Chain : Mansur bin Abi Mazahim (Bashir) – ‘Abdullah bin Mubarak – Abu Bakr bin ‘Uthman bin Sah