598
Musnad AhmedIt was narrated that Abu Umamah said:
"Ali (رضي الله عنه) said: I used to come to the Prophet (ﷺ) and ask permission to enter. If he was praying, he would say Subhan Allah, and if he was not praying, he would give me permission to enter.
Reference: Musnad Ahmad 598
Arabic/English book : Book 5, Hadith 598
Arabic/English book : Book 5, Hadith 598