Sahih Muslim Book - 6, Hadith - 1948

حَدَّثَنَا يَحْيَى بْنُ يَحْيَى قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ يَزِيدَ بْنِ رُومَانَ عَنْ صَالِحِ بْنِ خَوَّاتٍ عَمَّنْ صَلَّى مَعَ رَسُولِ اللَّهِ -صلى الله عليه وسلم- يَوْمَ ذَاتِ الرِّقَاعِ صَلاَةَ الْخَوْفِ أَنَّ طَائِفَةً صَفَّتْ مَعَهُ وَطَائِفَةٌ وِجَاهَ الْعَدُوِّ. فَصَلَّى بِالَّذِينَ مَعَهُ رَكْعَةً ثُمَّ ثَبَتَ قَائِمًا وَأَتَمُّوا لأَنْفُسِهِمْ. ثُمَّ انْصَرَفُوا فَصَفُّوا وِجَاهَ الْعَدُوِّ وَجَاءَتِ الطَّائِفَةُ الأُخْرَى فَصَلَّى بِهِمُ الرَّكْعَةَ الَّتِى بَقِيَتْ ثُمَّ ثَبَتَ جَالِسًا وَأَتَمُّوا لأَنْفُسِهِمْ ثُمَّ سَلَّمَ بِهِمْ.

It was narrated from Salih bin Khawwat, from those who had prayed the fear prayer with the Messenger of Allah (s.a.w) on the day of (the battle of) Dhat Ar-Riqa', that one group formed rows with him, and another group faced the enemy. He led those who were with him in praying one Rak'ah, then he remained standing and they completed the prayer by themselves. Then they moved away and faced the enemy, and the other group came. He led them in praying the remaining Rak'ah, then he remained sitting and they completed the prayer by themselves, then he said the Taslim with them.