حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ حَدَّثَنَا الْأَعْمَشُ عَنْ إِبْرَاهِيمَ عَنْ عَلْقَمَةَ عَنْ عَبْدِ اللَّهِ قَالَ كُنَّا نُسَلِّمُ عَلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَهُوَ فِي الصَّلَاةِ فَيَرُدُّ عَلَيْنَا فَلَمَّا رَجَعْنَا مِنْ عِنْدِ النَّجَاشِيِّ سَلَّمْنَا عَلَيْهِ فَلَمْ يَرُدَّ عَلَيْنَا فَقُلْنَا يَا رَسُولَ اللَّهِ كُنَّا نُسَلِّمُ عَلَيْكَ فِي الصَّلَاةِ فَتَرُدُّ عَلَيْنَا فَقَالَ إِنَّ فِيَّ أَوْ فِي الصَّلَاةِ لَشُغْلًا
مسند امام احمد بن حنبل · Hadith 3563
It was narrated that 'Abdullah (RA) said: We used to greet the Messenger of Allah (PBUH) with salam when he was praying, and he would return the greeting. When we came back from being with the Negus, we greeted him with salam and he did not return the greeting. We said: O Messenger of Allah, we used to greet you when you were praying and you would return the greeting. He said: "There is sufficient preoccupation in the prayer."
Sanad
حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ حَدَّثَنَا الْأَعْمَشُ عَنْ إِبْرَاهِيمَ عَنْ عَلْقَمَةَ عَنْ عَبْدِ اللَّهِ