كتاب إقامة الصلاة والسنة فيها
5  
Establishing the Prayer and the Sunnah Regarding Them
(59)
Chapter: If the greeting is given to a person who is performing Prayer, how should he respond?
(59)
باب الْمُصَلِّي يُسَلَّمُ عَلَيْهِ كَيْفَ يَرُدُّ
Sunan Ibn Majah 1018
It was narrated that Jabir said:
“The Prophet (ﷺ) sent me on an errand, then I caught up with him while he was performing prayer, and I greeted him. He gestured to me, then when he finished, he called me and said: ‘You greeted me before, but I was performing prayer.’”
حَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ الْمِصْرِيُّ، أَنْبَأَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنْ أَبِي الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ بَعَثَنِي النَّبِيُّ ـ صلى الله عليه وسلم ـ لِحَاجَةٍ ثُمَّ أَدْرَكْتُهُ وَهُوَ يُصَلِّي فَسَلَّمْتُ عَلَيْهِ فَأَشَارَ إِلَىَّ فَلَمَّا فَرَغَ دَعَانِي فَقَالَ ‏ "‏ إِنَّكَ سَلَّمْتَ عَلَىَّ آنِفًا وَأَنَا أُصَلِّي ‏"‏ ‏.‏
Grade: Sahih (Darussalam)
Reference : Sunan Ibn Majah 1018
In-book reference : Book 5, Hadith 216
English translation : Vol. 1, Book 5, Hadith 1018