An-Nisa' 4:102 واذا كنت فيهم فاقمت لهم الصلاة فلتقم طايفة منهم معك ولياخذوا اسلحتهم فاذا سجدوا فليكونوا من ورايكم ولتات طايفة اخرى لم يصلوا فليصلوا معك ولياخذوا حذرهم واسلحتهم ود الذين كفروا لو تغفلون عن اسلحتكم وامتعتكم فيميلون عليكم ميلة واحدة ولا جناح عليكم ان كان بكم اذى من مطر او كنتم مرضى ان تضعوا اسلحتكم وخذوا حذركم ان الله اعد للكافرين عذابا مهينا ١٠٢

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.