´It was narrated from Sahl bin Abu Hathmah that he said concerning the fear prayer:` “The Imam should stand facing the Qiblah, and a group of them should stand with him, and another group should stand in the direction of the enemy, facing towards the row (of worshippers). He should lead them in one Rak’ah, then they should bow and do two prostrations by themselves where they are. Then they should go and take the place of the others, and the others should come and pray one Rak’ah, bowing and prostrating with the leader. Then he will have prayed two Rak’ah and they will have prayed one; then they should perform another Rak’ah, bowing and performing two prostrations.”
Hadith Referenceسنن ابن ماجه / كتاب إقامة الصلاة والسنة / 1259
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:بخاري ومسلم
1؎: And for as long as it takes for the second group to complete this rak‘ah, the imam should remain seated in silence. When they finish the second rak‘ah, the imam should say the salam, and both groups should say the salam, because the prayer of both has been completed. And it is obligatory upon the first group to stand silently facing the enemy and not speak until the salam has been said.