O you who believe! be careful of (your duty to) Allah and be with the true ones. 119 It was not proper for the people of Madinah and those desert Arabs around them to hold back from following God's Messenger, and to prefer their own lives to his life. This is because whenever they suffer from thirst or weariness or hunger for God's cause, and whenever they take any step which provokes those who deny the truth, or inflicts any loss upon the enemy, it shall be counted as a good deed in the sight of God, God will not deny the righteous their reward, 120 Also, they would not have spent anything, great or small, for the cause of God or travel through a valley without God decreeing a reward for them far better than whatever 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