It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that once the Prophet (peace and blessings be upon him) led the companions in the Salat al-Khawf (prayer of fear). One row stood facing the enemy and one row stood behind the Prophet (peace and blessings be upon him). He led those behind him in one rak‘ah with one bowing and two prostrations. Then these people moved forward and stood in the place of their companions, and those people came here and stood in their place. The Prophet (peace and blessings be upon him) also led them in one rak‘ah with one bowing and two prostrations, and then he concluded the prayer with salam. In this way, the Prophet (peace and blessings be upon him) completed two rak‘ahs, and each of those people (in following the Prophet, peace and blessings be upon him) performed one rak‘ah.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 14180
Hadith Gradingحکم دارالسلام:إسناده صحيح، وقد اختلف الرواة عن جابر فى كيفية صلاة الخوف وعدد ركعاتها لكل من الامام والمامومين، فانظر: 14436 و 14928 و 14929 و 10190 و 15019، وانظر شرح السنة للبغوي: 280/4 - 286، و زادالمعاد: 229/1-532