Sahih Muslim 621
Sahih Muslim · Book 5: The Book of Mosques and Places of Prayer · It is recommended to pray `Asr early
Anas b. Malik reported:
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى ، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ إِسْحَاقَ بْنِ عَبْدِ اللَّهِ بْنِ أَبِي طَلْحَةَ ، عَنْ أَنَسِ بْنِ مَالِكٍ ، قَالَ كُنَّا نُصَلِّي الْعَصْرَ ثُمَّ يَخْرُجُ الإِنْسَانُ إِلَى بَنِي عَمْرِو بْنِ عَوْفٍ فَيَجِدُهُمْ يُصَلُّونَ الْعَصْرَ .
We used to offer the afternoon prayer (at such a time) that a person would go to Bani 'Amr b. Auf and he would find them busy offering the afternoon prayer.