باب يُسَلِّمُ حِينَ يُسَلِّمُ الإِمَامُ
Ibn 'Umar رضي الله عنهما liked for those offering Salat (prayers) behind the Imam to say Taslim (immediately) after the Imam had said it.
وَكَانَ ابْنُ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا يَسْتَحِبُّ إِذَا سَلَّمَ الإِمَامُ أَنْ يُسَلِّمَ مَنْ خَلْفَهُ.