Sahih Bukhari 1217

حَدَّثَنَا أَبُو مَعْمَرٍ ، حَدَّثَنَا عَبْدُ الْوَارِثِ ، حَدَّثَنَا كَثِيرُ بْنُ شِنْظِير ، عَنْ عَطَاءِ بْنِ أَبِي رَبَاحٍ ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ رَضِيَ اللَّهُ عَنْهُمَا , قَالَ : بَعَثَنِي رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي حَاجَةٍ لَهُ فَانْطَلَقْتُ ثُمَّ رَجَعْتُ وَقَدْ قَضَيْتُهَا ، فَأَتَيْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَسَلَّمْتُ عَلَيْهِ فَلَمْ يَرُدَّ عَلَيَّ فَوَقَعَ فِي قَلْبِي مَا اللَّهُ أَعْلَمُ بِهِ ، فَقُلْتُ فِي نَفْسِي لَعَلَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَجَدَ عَلَيَّ أَنِّي أَبْطَأْتُ عَلَيْهِ ، ثُمَّ سَلَّمْتُ عَلَيْهِ فَلَمْ يَرُدَّ عَلَيَّ فَوَقَعَ فِي قَلْبِي أَشَدُّ مِنَ الْمَرَّةِ الْأُولَى ، ثُمَّ سَلَّمْتُ عَلَيْهِ فَرَدَّ عَلَيَّ فَقَالَ : إِنَّمَا مَنَعَنِي أَنْ أَرُدَّ عَلَيْكَ أَنِّي كُنْتُ أُصَلِّي ، وَكَانَ عَلَى رَاحِلَتِهِ مُتَوَجِّهًا إِلَى غَيْرِ الْقِبْلَةِ .

Narrated Jabir bin `Abdullah: Allah's Apostle sent me for some job and when I had finished it I returned and came to the Prophet and greeted him but he did not return my greeting. So I felt so sorry that only Allah knows it and I said to myself,, 'Perhaps Allah's Apostle is angry because I did not come quickly, then again I greeted him but he did not reply. I felt even more sorry than I did the first time. Again I greeted him and he returned the greeting and said, The thing which prevented me from returning the greeting was that I was praying. And at that time he was on his Rahila and his face was not towards the Qibla.