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 And whosoever slayeth a believer intentionally, His meed is Hell, as an abider therein; and Allah shall be wroth with him and shall curse him, and shall get ready for him a torment terrible. 93 O you who have believed, when you go forth [to fight] in the cause of Allah, investigate; and do not say to one who gives you [a greeting of] peace "You are not a believer," aspiring for the goods of worldly life; for with Allah are many acquisitions. You [yourselves] were like that before; then Allah conferred His favor upon you, so investigate. Indeed Allah is ever, with what you do, Acquainted. 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 For them are higher ranks with God, and forgiveness and grace; and God is forgiving and kind. 96