Sahih Bukhari, Hadith: Q851, (157) Chapter. The staying of the Imam at his Musalla (praying place) after (finishing the prayer with) Taslim.

صحيح البخاري

Sahih Bukhari

كتاب الأذان (صفة الصلوة)

The Book of Adhan (Sufa-tus-Salat)

باب مكث الإمام فى مصلاه بعد السلام:

(157) Chapter. The staying of the Imam at his Musalla (praying place) after (finishing the prayer with) Taslim.