Sahih Al Bukhari Hadith Number 847

Narrated Anas bin Malik: Once the Prophet (peace be upon him) delayed the `Isha’ prayer until midnight and then came to us. Having prayed he faced us and said, “The people had prayed and slept but you were in the prayer as long as you were waiting for it.”

10  Call to Prayers (Adhaan)
Hadith number 847
Volume no 1
Chapter: 156(The Imam should face the followers after finishing the prayer with Taslim.)