Sunan an-Nasa'i, Volume 2, Book 14, Hadith 1420 (DarusSalam)

It was narrated that Anas said: "The Messenger of Allah would come down from the minbar and a man would come to him and speak to him, then the Prophet would listen to him until he gave him an answer, then he would go to his place of prayer and pray."

أَخْبَرَنِي مُحَمَّدُ بْنُ عَلِيِّ بْنِ مَيْمُونٍ، قَالَ حَدَّثَنَا الْفِرْيَابِيُّ، قَالَ حَدَّثَنَا جَرِيرُ بْنُ حَازِمٍ، عَنْ ثَابِتٍ الْبُنَانِيِّ، عَنْ أَنَسٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَنْزِلُ عَنِ الْمِنْبَرِ فَيَعْرِضُ لَهُ الرَّجُلُ فَيُكَلِّمُهُ فَيَقُومُ مَعَهُ النَّبِيُّ صلى الله عليه وسلم حَتَّى يَقْضِيَ حَاجَتَهُ ثُمَّ يَتَقَدَّمُ إِلَى مُصَلاَّهُ فَيُصَلِّي ‏.‏

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also referenced under: Book 14, Hadith 1430 (In-Book)