Sahih Muslim 833
Sahih Muslim · Book 6: The Book of Prayer - Travellers · Do not aim to pray when the sun is rising or setting
'A'isha said that the Messenger of Allah (ﷺ) did not abandon observing two rak'ahs after 'Asr, but she reported Allah's Messenger (ﷺ) as saying:
وَحَدَّثَنَا حَسَنٌ الْحُلْوَانِيُّ ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ ، أَخْبَرَنَا مَعْمَرٌ ، عَنِ ابْنِ طَاوُسٍ ، عَنْ أَبِيهِ ، عَنْ عَائِشَةَ ، أَنَّهَا قَالَتْ لَمْ يَدَعْ رَسُولُ اللَّهِ صلى الله عليه وسلم الرَّكْعَتَيْنِ بَعْدَ الْعَصْرِ . قَالَ فَقَالَتْ عَائِشَةُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ تَتَحَرَّوْا طُلُوعَ الشَّمْسِ وَلاَ غُرُوبَهَا فَتُصَلُّوا عِنْدَ ذَلِكَ " .
Do not get used to observe prayer at the time of the rising sun and at the time of its setting and (exhorted the Muslims) to pray at their times.