If the greeting is given to a person who is performing Prayer, how should he respond?
حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ الطَّنَافِسِيُّ، قَالَ حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، قَالَ أَتَى رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ مَسْجِدَ قُبَاءٍ يُصَلِّي فِيهِ، فَجَاءَتْ رِجَالٌ مِنَ الأَنْصَارِ يُسَلِّمُونَ عَلَيْهِ، فَسَأَلْتُ صُهَيْبًا، وَكَانَ مَعَهُ: كَيْفَ كَانَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ يَرُدُّ عَلَيْهِمْ؟ قَالَ: كَانَ يُشِيرُ بِيَدِهِ .
It was narrated that ‘Abdullah bin ‘Umar said: “The Messenger of Allah (ﷺ) came to the mosque at Quba’ and performed prayer there. Some men of the Ansar came and greeted him. I asked Suhaib, who was with him: ‘How did the Messenger of Allah (ﷺ) respond to them?’ He said: ‘He gestured with his hand.’”