O you who believe! be careful of (your duty to) Allah and be with the true ones. 119 The inhabitants of the city of Medina and the desert Arabs dwelling around it were not supposed to disobey the Messenger of God or to give priority to their own lives above that of the Prophet. For if they had given priority to the life of the Messenger of God, they would not have experienced the hardships of thirst, fatigue, or hunger in their struggle for the cause of God, nor would their travelling have enraged the disbelievers and they would not have received any injury from enemies that God would not record for them as a virtuous deed. God does not ignore the reward of those who do good. 120 There is not a sum, large or small, that they spend, not a piece of land that they traverse (in the service of God) which is not put down in their favour, so that God could reward them for what they had done. 121 ۞ With all this, it is not desirable that all of the believers take the field [in time of war]. From within every group in their midst, some shall refrain from going forth to war, and shall devote themselves [instead] to acquiring a deeper knowledge of the Faith and [thus be able to] teach their home-coming brethren, so that these [too] might guard themselves against evil. 122