Among mainstream Christianity, a growing sentiment endorses Christians taking up weapons for their own defense or the defense of others. Proponents argue that Christians are justified in killing in self-defense or in anticipation of a crime, believing society would be safer with a more fully armed citizenry. However, the sixth commandment is clear: You shall not murder (Exodus 20:13). The question remains whether killing to protect life or property falls into a gray area. God's instruction to the children of Israel, who were both a nation and a religious congregation, recognized only two classifications of killing: accidental and intentional. Self-defense is not listed as a possibility. Accidental death occurs without intent to kill or harm, as illustrated in Deuteronomy 19:5, where a man unintentionally causes a neighbor's death while cutting timber. Intentional killing, defined as murder, occurs when there is foreknowledge of potential harm, as stated in Exodus 21:12: He who strikes a man so that he dies shall surely be put to death. Firing a gun with the knowledge it could kill is considered murder under God's law, regardless of the threat posed by the other person. Human nature often insists on a self-clause, suggesting God's law can be suspended when it conflicts with perceived best interests. Yet, God does not allow the suspension of His law, even under threat. Intentionally taking a life in defense of self prioritizes self over God, demonstrating enmity against Him, as described in Romans 8:7. In doing so, one acts as judge, jury, and executioner, presuming authority not granted by God, who reserves the right to determine right and wrong. Under the New Covenant, God does not promise complete protection from violence, as seen in various scriptures. Faithful Christians may suffer violence, either as a consequence of actions or as part of God's purpose, which may not be immediately discernible. Yet, if called by God and loving Him, we have His promise that all things work together for good (Romans 8:28). Some view God's prohibition against killing as weak, but true strength lies in abiding by His law and trusting in His will, rather than relying on self. Faith in God's sovereignty determines our responses, even when threatened, believing in His ability to accomplish His purpose. Exodus 22:2-3 clarifies that killing a thief in the dark may be considered accidental due to impaired judgment, but killing in clear circumstances is intentional and deemed murder. Jesus Christ teaches that murder begins in the heart with intent, reinforcing that intentional killing, even in defense, is against God's law (Matthew 5:21-22).

The breaking of the sixth commandment, which forbids murder, reveals the immediate and devastating effect of sin through the loss of life and the separation it causes. Sin, as declared in Romans 6:23, brings death, the ultimate form of separation, with no alternatives in its wake. Murder stands as a grave sin, evidenced by staggering statistics: in the United States alone, between 2003 and 2006, there were 66,460 murders, with 16,692 in 2005. Globally, the problem of taking human life is immeasurable. Abortion, deemed the foulest of murders, claims approximately 1.37 million lives annually in the United States and 46 million worldwide, extinguishing the most innocent and helpless. Suicide, a form of self-murder, accounted for 32,637 deaths in the United States in 2005, surpassing the number of murders by others in the same period, with 815,925 additional failed attempts. War represents the most effective and rapid means of killing, with historical records estimating 500 million deaths in the twenty most devastating conflicts. Modern holy wars, marked by bombings and assassinations, justify slaughter under the guise of righteousness, with perpetrators believing their victims deserve death. Such attitudes, seen in various religious and cultural contexts, transform killing into a perceived justifiable act. Even in secular contexts, war is rationalized as necessary, with rhetoric invoking evil and justifying mass destruction as a fight against malevolent forces. This belief in just war convinces many to participate in killings, viewing their actions as a noble sacrifice. However, the sixth commandment offers no permission for deliberate killing, regardless of justifications like love of country. Jesus Christ, in Matthew 15:18-20, emphasizes that premeditated murder differs from accidental killing, and while civil authorities are permitted to enact the death penalty under specific circumstances, no sanctuary exists for deliberate murderers. Numbers 35:9-34 details cities of refuge for accidental killers, where they must remain until the high priest's death, subject to trial and potential vengeance by a family avenger if they leave. Deuteronomy 19:15-21 underscores God's concern for fair judgment in such cases. Jesus Christ further teaches against retaliation, urging the removal of bitterness from the heart and advocating for good over evil in response to minor provocations, as seen in Matthew 5:38-39. He exemplifies this in Luke 23:34, forgiving those who crucified Him, prioritizing His mission over personal retribution. Paul, in Romans 12:17-20, aligns with this teaching, insisting that vengeance belongs to God alone, not to individuals driven by a desire for retaliation. This principle, rooted in faith, asserts that God, who fully understands all circumstances, retains the sole right to judge and avenge. Thus, Christians are called to reject the spirit of murder and retaliation, trusting in God's ultimate authority over such matters.

The issue of killing and justification for it often intertwines with the concept of holy war, where violence is perpetrated in the name of God across various cultures and religions. Militant terrorists, driven by passionate conviction of their righteousness, claim credit for the slaughter of innocents, judging themselves beyond crime or sin. Holy wars, marked by fear and bloodshed, are not confined to any single faith, as seen in the jihad of Islam, the kamikaze doctrine of Shintoism, and conflicts among Christians and Muslims in places like Beirut. Even in supposedly secular contexts, wars deemed sensible, necessary, and just require stirring anger and hatred to persuade ordinarily peaceful citizens to kill, mirroring the frenzy of holy wars elsewhere. Secretaries of Defense calmly appraise risks and demand resources for preparedness to kill, using rhetoric that labels enemies as evil empires or antichrists, revealing a form of holy war rhetoric in disguise. God's supremacy over nations is evident in scriptures where He grants dominion and promises to fight supernaturally for His people, provided they obey Him. Yet, Israel's history shows a pattern of distrust and disobedience, often leading to dissatisfaction and war. Despite God's repeated offers to fight for them, as seen in moments like the parting of the Red Sea, Israel's weak faith and chronic doubt pushed them toward conflict, even when God allowed it as a consequence of their choices. The central fact remains that God has commanded not to kill, and obedience to this, coupled with faith in His promises, means never resorting to killing, as He will intervene to fight battles on behalf of His obedient followers. However, when the Kingdom of God is established on earth, participation in battle is foretold, contrasting with the current status of believers as ambassadors and sojourners who must not involve themselves in the wars of human nations, reserving fullest allegiance to God in heaven.