(24) باب هَلْ يَخْرُجُ مِنَ الْمَسْجِدِ لِعِلَّةٍ
Narrated Abu Huraira:
Allah's Messenger (ﷺ) went out (of the mosque) when the Iqama had been pronounced and the rows straightened. The Prophet (ﷺ) stood at his Musalla (praying place) and we waited for the Prophet (ﷺ) to begin the prayer with Takbir. He left and asked us to remain in our places. We kept on standing till the Prophet returned and the water was trickling from his head for he had taken a bath (of Janaba).
Reference: Sahih al-Bukhari 639
In-book reference: Book 10, Hadith 36
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 11, Hadith 612