Fear Prayer

Narrated Shu'aib:
I asked Az−Zuhri, "Did the Prophet ever offer the Fear
Prayer?" Az−Zuhri said, "I was told by Salim that `Abdullah
bin `Umar I had said, 'I took part in a holy battle with
Allah's Apostle I in Najd. We faced the enemy and arranged
ourselves in rows. Then Allah's Apostle (p.b.u.h) stood up to
lead the prayer and one party stood to pray with him while the
other faced the enemy. Allah's Apostle (p.b.u.h) and the
former party bowed and performed two prostrations. Then that
party left and took the place of those who had not prayed.
Allah's Apostle prayed one rak`a (with the latter) and
performed two prostrations and finished his prayer with
Taslim. Then everyone of them bowed once and performed two
prostrations individually.' " Bukhari 2/64