صحيح ابن خزيمه
Sahih Ibn Khuzaymah
جماع أبواب صلاة الخوفChapters on Fear Prayer
(626)- بَابٌ فِي صَلَاةِ الْخَوْفِ أَيْضًا إِذَا كَانَ الْعَدُوُّ خَلْفَ الْقِبْلَةِ626| The fear prayer when the enemy is behind the qiblah
Hadith Q1354
وَالرُّخْصَةِ لِلطَّائِفَةِ الْأُولَى فِي تَرْكِ اسْتِقْبَالِهَا الْقِبْلَةَ بَعْدَ فَرَاغِهَا مِنَ الرَّكْعَةِ الْأُولَى لِتَحْرُسَ الطَّائِفَةَ الثَّانِيَةَ مِنَ الْعَدُوِّ وَقَضَاءِ الطَّائِفَتَيْنِ الرَّكْعَةَ الثَّانِيَةَ بَعْدَ تَسْلِيمِ الْإِمَامِ
So, after the first group has finished the first rak‘ah, the second group is permitted to abandon facing the qiblah in order to protect against the enemy—and the explanation of both groups completing the second rak‘ah after the imam has said the salām.
