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

When you [Prophet] are with the believers, leading them in prayer, let a group of them stand up in prayer with you, taking their weapons with them, and when they have finished their prostration, let them take up their positions at the back. Then let the other group, who have not yet prayed, pray with you, also on their guard and armed with their weapons: the disbelievers would dearly like you to be heedless of your weapons and baggage, in order for them to take you in a single assault. You will not be blamed if you lay aside your arms when you are overtaken by heavy rain or illness, but be on your guard. Indeed, God has prepared a humiliating punishment for the disbelievers.