Salih bin Khawwat (may Allah have mercy on him) narrates from his father (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) led the fear prayer. One group was with him (peace and blessings be upon him) and the other was facing the enemy. The Prophet (peace and blessings be upon him) led those who were with him (peace and blessings be upon him) in one rak'ah; then he (peace and blessings be upon him) stood up, and they stood and completed their prayer. Then they went to the place of their companions and the other group came, and the Prophet (peace and blessings be upon him) led them in the one rak'ah that remained; then they completed their prayer. Ubaydullah (may Allah have mercy on him) said that al-Qasim (may Allah have mercy on him) said: I have not heard anything about the fear prayer more beloved to me than this.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخوف / 6010