Bukhari

Hadith Commentary:
(1)
The Messenger of Allah (sallallahu alayhi wa sallam) forbade people from performing prayer at two times, that is, after the morning (Fajr) and afternoon (‘Asr) prayers. However, after the second arrival of the delegation of ‘Abd al-Qays, he (sallallahu alayhi wa sallam) made a point of performing two rak‘ahs after ‘Asr in the house of Umm Salamah (radi Allahu anha). When the noble wife observed what appeared to be a contradiction between his statement and his action, she inquired about the reason. The Messenger of Allah (sallallahu alayhi wa sallam) informed her of his excuse: due to being occupied, he had not been able to perform the two rak‘ahs after the Zuhr (noon) prayer, so he was now making them up.
(Musnad Ahmad: 310/6)
But after this, he continued this practice openly in the house of ‘A’ishah (radi Allahu anha).
(Sunan al-Nasa’i, al-Mawaqit, Hadith: 578)
However, he kept this hidden from other people, lest they consider it a Sunnah and begin to perform it regularly.
As for ‘A’ishah (radi Allahu anha), he was certain that, despite seeing him perform it regularly even after forbidding others, she would attribute it to a specific circumstance. Yet, despite her intelligence and acumen, this matter remained hidden from her, and she considered this action of the Messenger of Allah (sallallahu alayhi wa sallam) to be Sunnah, and she mentioned various reasons for the prohibition, one of which was that people should not be subjected to unnecessary hardship, for the Messenger of Allah (sallallahu alayhi wa sallam) liked to make things easy for people.
(Sahih al-Bukhari, Mawaqit al-Salat, Hadith: 590)
Also, the prohibition pertains to the case of intentionally performing prayer at those times, as he (sallallahu alayhi wa sallam) expressed regarding ‘Umar (radi Allahu anhu) in these words: he was under the impression that the Messenger of Allah (sallallahu alayhi wa sallam) forbade only in the case of intentional performance.
(Sahih Muslim, al-Masajid, Hadith: 1931(833))
It should be noted that ‘Umar (radi Allahu anhu) used to strike those who performed two rak‘ahs after ‘Asr.
(Sahih al-Bukhari, al-Sahw, Hadith: 1233) (2)
Hafiz Ibn Hajar (rahimahullah) writes that from the continual practice of the Messenger of Allah (sallallahu alayhi wa sallam) of performing two rak‘ahs after ‘Asr, ‘A’ishah (radi Allahu anha) understood that the prohibition of performing supererogatory prayers after ‘Asr until sunset was not absolute, but rather applied to the person who deliberately and intentionally performed prayer at the time of sunset.
For this reason, she herself used to perform supererogatory prayers after ‘Asr.
‘Abdullah ibn al-Zubayr (radi Allahu anhu) also understood it this way and continued to perform two rak‘ahs after ‘Asr.
(Fath al-Bari: 87/2)