ذِكْرُ الْإِبَاحَةِ لِلْمُصَلِّي أَنْ يُصَلِّيَ عَلَى رَاحِلَتِهِ وَإِنْ كَانَتِ الْقِبْلَةُ وَرَاءَهُ
"The Messenger of Allah ﷺ sent me on an errand then I came back to him while he was praying. I greeted him with the salam and he gestured to me. When he finished he called me and said: 'You greeted me with Salam just now and I was praying.' And he was facing toward the east that day." (Using translation from Nasāʾī 1189)
بَعَثَنِي رَسُولُ اللَّهِ ﷺ فِي حَاجَةٍ فَأَدْرَكْتُهُ فَسَلَّمْتُ عَلَيْهِ وَهُوَ يُصَلِّي فَأَشَارَ إِلَيَّ فَلَمَّا فَرَغَ دَعَانِي فَقَالَ «إِنَّكَ سَلَّمْتَ عَلَيَّ وَأَنَا أُصَلِّي» وَهُوَ مُتَوَجِّهٌ يَوْمَئِذٍ نَحْوَ الْمَشْرِقِ