"There are two prayers that the Messenger of Allah (ﷺ) never neglected to pray them in my house secretly nor publicly: Two Rak'ahs before Fajr and two Rak'ahs after 'Asr."
Sunan an-Nasa'i Book 6, Hadith 84
← Previous Hadith "I heard Masruq and Al-Aswad say: We bear witness that 'Aishah said: 'When the Messenger of Allah (ﷺ) was with me after 'Asr, he would pray them (these two Rak'ahs).'"

Sunan an-Nasa'i Book 6, Hadith 83 Next Hadith → "He used to pray them before 'Asr, but if he got distracted or forgot them, he would pray them after 'Asr, and if he did a prayer he would be constant in it."

Sunan an-Nasa'i Book 6, Hadith 85