An-Nisa (As Mulheres) 4:102

<h2>The Description of The Fear Prayer</h2><p>The Fear prayer has different forms, for the enemy is sometimes in the direction of the Qiblah and sometimes in another direction. The Fear prayer consists sometimes of four Rak`ahs, three Rak`ahs, as for Maghrib, and sometimes two Rak`ah like Fajr and prayer during travel. The Fear prayer is sometimes prayed in congregation, but when the battle is raging, congregational prayer may not be possible. In this case, they pray each by himself, facing the Qiblah or otherwise, riding or on foot. In this situation, they are allowed to walk and fight, all the while performing the acts of the prayer. Some scholars said that in the latter case, they pray only one Rak`ah, for Ibn `Abbas narrated, "By the words of your Prophet , Allah has ordained the prayer of four Rak`ah while residing, two Rak`ah during travel, and one Rak`ah during fear." Muslim, Abu Dawud, An-Nasa'i and Ibn Majah recorded it. This is also the view of Ahmad bin Hanbal. Al-Mundhiri said, "This is the saying of `Ata', Jabir, Al-Hasan, Mujahid, Al-Hakam, Qatadah and Hammad; and Tawus and Ad-Dahhak also prefered it." Abu `Asim Al-`Abadi mentioned that Muhammad bin Nasr Al-Marwazi said the …

And when thou (O Muhammad) art among them and arrangest (their) worship for them, let only a party of them stand with thee (to worship) and let them take their arms. Then when they have performed their prostrations let them fall to the rear and let another party come that hath not worshipped and let them worship with thee, and let them take their precaution and their arms. Those who disbelieve long for you to neglect your arms and your baggage that they may attack you once for all. It is no sin for you to lay aside your arms, if rain impedeth you or ye are sick. But take your precaution. Lo! Allah prepareth for the disbelievers shameful punishment.

When thou (O Messenger) art with them, and standest to lead them in prayer, Let one party of them stand up (in prayer) with thee, Taking their arms with them: When they finish their prostrations, let them Take their position in the rear. And let the other party come up which hath not yet prayed - and let them pray with thee, Taking all precaution, and bearing arms: the Unbelievers wish, if ye were negligent of your arms and your baggage, to assault you in a single rush. But there is no blame on you if ye put away your arms because of the inconvenience of rain or because ye are ill; but take (every) precaution for yourselves. For the Unbelievers Allah hath prepared a humiliating punishment.

When you (O Messenger Muhammad SAW) are among them, and lead them in As-Salat (the prayer), let one party of them stand up [in Salat (prayer)] with you taking their arms with them; when they finish their prostrations, let them take their positions in the rear and let the other party come up which has not yet prayed, and let them pray with you taking all the precautions and bearing arms. Those who disbelieve wish, if you were negligent of your arms and your baggage, to attack you in a single rush, but there is no sin on you if you put away your arms because of the inconvenience of rain or because you are ill, but take every precaution for yourselves. Verily, Allah has prepared a humiliating torment for the disbelievers.

When you are among them, and you stand to lead them in prayer, let a group of them stand with you, and let them hold their weapons. Then, when they have done their prostrations, let them withdraw to the rear, and let another group, that have not prayed yet, come forward and pray with you; and let them take their precautions and their weapons. Those who disbelieve would like you to neglect your weapons and your equipment, so they can attack you in a single assault. You commit no error, if you are hampered by rain or are sick, by putting down your weapons; but take precautions. Indeed, God has prepared for the disbelievers a demeaning punishment.