There is a disease in their hearts, so Allah added to their disease and they shall have a painful chastisement because they

And when you are among them and keep up the prayer for them, let a party of them stand up with you, and let them take their arms; then when they have prostrated themselves let them go to your rear, and let another party who have not prayed come forward and pray with you, and let them take their precautions and their arms; (for) those who disbelieve desire that you may be careless of your arms and your luggage, so that they may then turn upon you with a sudden united attack, and there is no blame on you, if you are annoyed with rain or if you are sick, that you lay down your arms, and take your precautions; surely Allah has prepared a disgraceful chastisement for the unbelievers.

There is no harm in the blind, nor is there any harm in the lame, nor is there any harm in the sick (if they do not go forth); and whoever obeys Allah and His Messenger, He will cause him to enter gardens beneath which rivers flow, and whoever turns back, He will punish him with a painful punishment.