Sunan Abi Dawud Book 5, Hadith 31
Dhakwan, the client of Aisha, reported on the authority of Aisha: The Messenger of Allah (ﷺ) used to pray after the afternoon prayer but prohibited others from it; and he would fast continuously but forbid others to do so.
We bear witness that 'Aishah said: Not a day passed but the Prophet (ﷺ) prayed two rak'ahs after the 'Asr prayer
The Messenger of Allah (ﷺ) said: Pray two rak'ahs before the Maghrib prayer. He then said (again): Pray two rak'ahs before the Maghrib prayer, it applies to those who wish to do so. That was because he feared that the people might treat it as sunnah.