(54) باب مَعْرِفَةِ الرَّكْعَتَيْنِ اللَّتَيْنِ كَانَ يُصَلِّيهِمَا النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بَعْدَ الْعَصْرِ
Abu Salama asked 'A'isha about the two prostrations (i. e. rak'ahs) which the Messenger of Allah (ﷺ) made after the 'Asr. She said:
He (the Holy Prophet) observed them before the 'Asr prayer, but then he was hindered to do so, or he forgot them and then he observed them after the 'Asr, and then he continued observing them. (It was his habit) that when he (the Holy Prophet) observed prayer, he then continued observing it. Isma'il said: It implies that he always did that.
Reference: Sahih Muslim 835 a
In-book reference: Book 6, Hadith 362
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1816