It is not rightful for a Muslim to kill another Muslim, unless it occurs by mistake; and the one who mistakenly kills a Muslim must set free a Muslim slave and pay blood-money to the family of the slain, except if they forego it; and if the victim is of a people who are hostile to you, and the killer is a Muslim, then only the setting free of a Muslim slave (is obligatory); and if the victim is from a people between whom and you there is a treaty, then blood-money must be paid to his family and the setting free of a Muslim slave; therefore one who has no means must fast for two consecutive months; this is his penance before Allah; and Allah is All Knowing, Wise. 92 Whoso slayeth a believer of set purpose, his reward is hell for ever. Allah is wroth against him and He hath cursed him and prepared for him an awful doom. 93 Believers! When you go forth in the way of Allah, discern (between friend and foe), and do not say to him who offers you the greeting of peace: 'You are not a believer.' If you seek the good of this worldly life, there lies with Allah abundant gain. After all, you too were such before, and then Allah was gracious to you. Discern, then, for Allah is well aware of what you do. 94 Those believers who stay behind, apart from those forced by necessity, are not equal to those who strive hard in God's cause with their possessions and their persons. God has given those who strive with their goods and their persons a higher rank than those who stayed behind. God has promised all a good reward; but far greater is the recompense of those who strive for Him -- 95 in ranks standing before Him, forgiveness and mercy; surely God is All-forgiving, All-compassionate. 96