وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ، عَنْ صَالِحِ بْنِ خَوَّاتٍ، أَنَّ سَهْلَ بْنَ أَبِي حَثْمَةَ، حَدَّثَهُ أَنَّ صَلاَةَ الْخَوْفِ أَنْ يَقُومَ الإِمَامُ وَمَعَهُ طَائِفَةٌ مِنْ أَصْحَابِهِ وَطَائِفَةٌ مُوَاجِهَةٌ الْعَدُوَّ فَيَرْكَعُ الإِمَامُ رَكْعَةً وَيَسْجُدُ بِالَّذِينَ مَعَهُ ثُمَّ يَقُومُ فَإِذَا اسْتَوَى قَائِمًا ثَبَتَ وَأَتَمُّوا لأَنْفُسِهِمُ الرَّكْعَةَ الْبَاقِيَةَ ثُمَّ يُسَلِّمُونَ وَيَنْصَرِفُونَ وَالإِمَامُ قَائِمٌ فَيَكُونُونَ وِجَاهَ الْعَدُوِّ ثُمَّ يُقْبِلُ الآخَرُونَ الَّذِينَ لَمْ يُصَلُّوا فَيُكَبِّرُونَ وَرَاءَ الإِمَامِ فَيَرْكَعُ بِهِمُ الرَّكْعَةَ وَيَسْجُدُ ثُمَّ يُسَلِّمُ فَيَقُومُونَ فَيَرْكَعُونَ لأَنْفُسِهِمُ الرَّكْعَةَ الْبَاقِيَةَ ثُمَّ يُسَلِّمُونَ ‏.‏

Yahya related to me from Malik from Yahya ibn Said from al-Qasimibn Muhammad from Salih ibn Khawwat that Sahl ibn Abi Hathma relatedto him that the form of the prayer of fear was that the imam stoodwith a group of his companions, while another group faced the enemy.The imam prayed one raka with them, including the prostration, andthen stood. He remained standing while they completed the remainingraka by themselves. They then said the taslim, left, and formed upopposite the enemy while the imam remained standing. Then the otherswho had not prayed came forward and said the takbir behind the imamand he prayed one raka with them, including the prostration. He thensaid the taslim, while they stood up and prayed the remaining raka bythemselves. Then they said the taslim. Translation Not Available

Book reference: Muwatta Imam Malik Book 11 Hadith 445
Web reference: Muwatta Imam Malik Book 11 Hadith 2