Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
muslim:839c – Abū Bakr b. Abū Shaybah > Yaḥyá b. Ādam > Sufyān > Mūsá b. ʿUqbah > Nāfiʿ > Ibn ʿUmar

a group stood with him (the Holy Prophet) (for prayer) and the other group stood In front of the enemy. Then those who were with (him) observed one rak'ah of prayer and they went back and the others came and they observed one rak'ah (with him). Then both the groups completed one rak'ah each. Ibn Umar said: When there is greater danger, then observe prayer even on the ride or with the help of gestures in a standing posture.  

مسلم:٨٣٩c – وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ حَدَّثَنَا يَحْيَى بْنُ آدَمَ عَنْ سُفْيَانَ عَنْ مُوسَى بْنِ عُقْبَةَ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ قَالَ

صَلَّى رَسُولُ اللَّهِ ﷺ صَلاَةَ الْخَوْفِ فِي بَعْضِ أَيَّامِهِ فَقَامَتْ طَائِفَةٌ مَعَهُ وَطَائِفَةٌ بِإِزَاءِ الْعَدُوِّ فَصَلَّى بِالَّذِينَ مَعَهُ رَكْعَةً ثُمَّ ذَهَبُوا وَجَاءَ الآخَرُونَ فَصَلَّى بِهِمْ رَكْعَةً ثُمَّ قَضَتِ الطَّائِفَتَانِ رَكْعَةً رَكْعَةً قَالَ وَقَالَ ابْنُ عُمَرَ فَإِذَا كَانَ خَوْفٌ أَكْثَرَ مِنْ ذَلِكَ فَصَلِّ رَاكِبًا أَوْ قَائِمًا تُومِئُ إِيمَاءً  

See similar narrations below:

Collected by Nasāʾī, Aḥmad, Nasāʾī's Kubrá
nasai:1542 – ʿAbd al-Aʿlá b. Wāṣil b. ʿAbd al-Aʿlá > Yaḥyá b. Ādam > Sufyān > Mūsá b. ʿUqbah > Nāfiʿ > Ibn ʿUmar

"The Messenger of Allah ﷺ offered the fear prayer during one of his battles. One group stood with him and another group faced the enemy. He led those who were with him in praying one rak'ah, then they went away and the others came, and he led them in praying one rak'ah. Then each group made up one rak'ah."  

النسائي:١٥٤٢ – أَخْبَرَنَا عَبْدُ الأَعْلَى بْنُ وَاصِلِ بْنِ عَبْدِ الأَعْلَى قَالَ حَدَّثَنَا يَحْيَى بْنُ آدَمَ عَنْ سُفْيَانَ عَنْ مُوسَى بْنِ عُقْبَةَ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ قَالَ

صَلَّى رَسُولُ اللَّهِ ﷺ صَلاَةَ الْخَوْفِ فِي بَعْضِ أَيَّامِهِ فَقَامَتْ طَائِفَةٌ مَعَهُ وَطَائِفَةٌ بِإِزَاءِ الْعَدُوِّ فَصَلَّى بِالَّذِينَ مَعَهُ رَكْعَةً ثُمَّ ذَهَبُوا وَجَاءَ الآخَرُونَ فَصَلَّى بِهِمْ رَكْعَةً ثُمَّ قَضَتِ الطَّائِفَتَانِ رَكْعَةً رَكْعَةً  

ahmad:6431 – Yaḥyá b. Ādam > Sufyān > Mūsá b. ʿUqbah > Nāfiʿʿan Ibn ʿUmar

"The Messenger of Allah ﷺ offered the fear prayer during one of his battles. One group stood with him and another group faced the enemy. He led those who were with him in praying one rak'ah, then they went away and the others came, and he led them in praying one rak'ah. Then each group made up one rak'ah." (Using translation from Nasāʾī 1542)  

أحمد:٦٤٣١ – حَدَّثَنَا يَحْيَى بْنُ آدَمَ حَدَّثَنَا سُفْيَانُ عَنْ مُوسَى بْنِ عُقْبَةَ عَنْ نَافِعٍعَنِ ابْنِ عُمَرَ قَالَ

صَلَّى رَسُولُ اللهِ ﷺ صَلَاةَ الْخَوْفِ فِي بَعْضِ أَيَّامِهِ فَقَامَتْ طَائِفَةٌ مَعَهُ وَطَائِفَةٌ بِإِزَاءِ الْعَدُوِّ فَصَلَّى بِالَّذِينَ مَعَهُ رَكْعَةً ثُمَّ ذَهَبُوا وَجَاءَ الْآخَرُونَ فَصَلَّى بِهِمْ رَكْعَةً ثُمَّ قَضَتِ الطَّائِفَتَانِ رَكْعَةً رَكْعَةً  

nasai-kubra:1943 – ʿAbd al-Aʿlá b. Wāṣil b. ʿAbd al-Aʿlá > Yaḥyá b. Ādam > Sufyān > Mūsá b. ʿUqbah > Nāfiʿ > Ibn ʿUmar

"The Messenger of Allah ﷺ offered the fear prayer during one of his battles. One group stood with him and another group faced the enemy. He led those who were with him in praying one rak'ah, then they went away and the others came, and he led them in praying one rak'ah. Then each group made up one rak'ah." (Using translation from Nasāʾī 1542)  

الكبرى للنسائي:١٩٤٣ – أَخْبَرَنَا عَبْدُ الْأَعْلَى بْنُ وَاصِلِ بْنِ عَبْدِ الْأَعْلَى قَالَ حَدَّثَنَا يَحْيَى بْنُ آدَمَ عَنْ سُفْيَانَ عَنْ مُوسَى بْنِ عُقْبَةَ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ قَالَ

«صَلَّى رَسُولُ اللهِ ﷺ صَلَاةَ الْخَوْفِ فِي بَعْضِ أَيَّامِهِ فَقَامَتْ طَائِفَةٌ مَعَهُ وَطَائِفَةٌ بِإِزَاءِ الْعَدُوِّ فَصَلَّى بِالَّذِينَ مَعَهُ رَكْعَةً ثُمَّ ذَهَبُوا وَجَاءَ الْآخَرُونَ فَصَلَّى بِهِمْ رَكْعَةً ثُمَّ قَضَتِ الطَّائِفَةُ رَكْعَةً رَكْعَةً»