Sahih Muslim 605 a
Abu Salama son of Abd al-Rahman b. Auf reported Abu Huraira as saying:
Iqama was pronounced and we stood up and made rows straight till he (the Holy Prophet) stood at his place of worship (the place ahead of the rows where he stood to lead the prayer) before takbir tahrima. He reminded to (himself something) and went back saying that we should stand at our places and not leave them. We waited, till he came back to us and he had taken a bath and water trickled out of his head and then led us in prayer.
حَدَّثَنَا هَارُونُ بْنُ مَعْرُوفٍ، وَحَرْمَلَةُ بْنُ يَحْيَى، قَالاَ حَدَّثَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي أَبُو سَلَمَةَ بْنُ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ، سَمِعَ أَبَا هُرَيْرَةَ، يَقُولُ أُقِيمَتِ الصَّلاَةُ فَقُمْنَا فَعَدَّلْنَا الصُّفُوفَ قَبْلَ أَنْ يَخْرُجَ إِلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَأَتَى رَسُولُ اللَّهِ صلى الله عليه وسلم حَتَّى إِذَا قَامَ فِي مُصَلاَّهُ قَبْلَ أَنْ يُكَبِّرَ ذَكَرَ فَانْصَرَفَ وَقَالَ لَنَا ‏
"‏ مَكَانَكُمْ ‏"‏ ‏.‏ فَلَمْ نَزَلْ قِيَامًا نَنْتَظِرُهُ حَتَّى خَرَجَ إِلَيْنَا وَقَدِ اغْتَسَلَ يَنْطِفُ رَأْسُهُ مَاءً فَكَبَّرَ فَصَلَّى بِنَا ‏.‏