And the prayer of the imam with each group is two rak‘ahs, and this is also the type which I have informed of the permissibility of the follower performing an obligatory prayer behind an imam who is praying a voluntary prayer; since one of the two rak‘ahs was for the Prophet, peace and blessings be upon him, a voluntary act, and for the followers an obligation.

Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) narrates that he performed the prayer of fear with the Messenger of Allah (peace be upon him). The Messenger of Allah (peace be upon him) led one group in two rak‘ahs, then led the other group in two rak‘ahs. In this way, the Messenger of Allah (peace be upon him) prayed four rak‘ahs and led each group in two rak‘ahs.