Sunan an-Nasa'i, Volume 1, Book 6, Hadith 510 (DarusSalam) ⓘ

It was narrated that Abu Bakr bin 'Uthman bin Sahl bin Hunaif said: "I heard Abu Umamah bin Sahl say: 'We prayed Zuhr with 'Umar bin 'Abdul-'Aziz, then we went out and entered upon Anas bin Malik, and we found him praying 'Asr.'" I said: "O uncle, what is this prayer that you prayed?" He said: "'Asr; this is the prayer of the Messenger of Allah that we used to pray with him."

أَخْبَرَنَا سُوَيْدُ بْنُ نَصْرٍ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، 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 قُلْتُ يَا عَمِّ مَا هَذِهِ الصَّلاَةُ الَّتِي صَلَّيْتَ قَالَ الْعَصْرَ وَهَذِهِ صَلاَةُ رَسُولِ اللَّهِ صلى الله عليه وسلم الَّتِي كُنَّا نُصَلِّي ‏.‏