كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5  
The Book of Mosques and Places of Prayer
(29)
Chapter: When should the people stand up to pray?
(29)
باب مَتَى يَقُومُ النَّاسُ لِلصَّلاَةِ ‏
Sahih Muslim 605 b

Abu Salama reported Abu Huraira as saying:

Iqama was pronounced. ant the people had formed themselves into rows. The Messenger of Allah (ﷺ) came out and stood at his place, and then pointed out with his hand that we should stand at our places. He then went away and took a bath and water trickled from his head and then led them in prayer.
وَحَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا الْوَلِيدُ بْنُ مُسْلِمٍ، حَدَّثَنَا أَبُو عَمْرٍو، - يَعْنِي الأَوْزَاعِيَّ - حَدَّثَنَا الزُّهْرِيُّ، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ أُقِيمَتِ الصَّلاَةُ وَصَفَّ النَّاسُ صُفُوفَهُمْ وَخَرَجَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَامَ مَقَامَهُ فَأَوْمَأَ إِلَيْهِمْ بِيَدِهِ أَنْ ‏ "‏ مَكَانَكُمْ ‏"‏ ‏.‏ فَخَرَجَ وَقَدِ اغْتَسَلَ وَرَأْسُهُ يَنْطِفُ الْمَاءَ فَصَلَّى بِهِمْ ‏.‏
Reference : Sahih Muslim 605b
In-book reference : Book 5, Hadith 202
USC-MSA web (English) reference : Book 4, Hadith 1257
  (deprecated numbering scheme)