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.

The Holy Quran · An-Nisaa (The Women) · 4:102