(53) باب لاَ تَتَحَرَّوْا بِصَلاَتِكُمْ طُلُوعَ الشَّمْسِ وَلاَ غُرُوبَهَا
'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:
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.
Reference: Sahih Muslim 833 b
In-book reference: Book 6, Hadith 360
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1814