I’m confused on why the ten commandments included the law "you shall not kill." Are there exceptions to this rule? Moses himself ordered the death of some people because they sinned against God (Exodus 32: 19-28). And despite the constant wars that occur in the Bible, God even orders his people to kill children (1 Samuel 15: 1-3)
The commandment "You shall not kill" was a referene to a single human being taking law and life into his or her own hands and taking the life of another person. It is not a prohibition against a nation having a police force and an army. We do not have the right to simply decide for ourselves to take the life of another. Are there exceptions to this principle? First of all, warfare is not really an exception. This is a state-sponsored activity. Obviously, governments have a right and even a duty to defend their people against agression. God gave Israel in the Old Testament the right and in some cases even the commandment to defend itself and to make war. This is not a contradiction of The Bible never says that a government does not have the right to defend itself. Paul said that the government does not carry the sword in vain (Romans 13:4). I am personally strongly opposed to the death penalty. I also believe that Jesus would be opposed to the death penalty as well, as he was a pacificst and preached love. Nevertheless, having said that, God has given nations and governments the right to enact laws, including the death penalty.
You are asking if there are any exceptions. Let me slightly reword the question. Are there any exceptions to the rule that a single human being does not have the right, under any circumstances, to take the life of another single human being for their own purposes? My answer is that perhaps it may not be sinful to take the life of another in self defense or in defense of one’s family. Surely, God gives the right to police officers to use force to defend the rights of innocent civillians. Having said that, is it acceptable for a Christian to defend his own life or home against a violent criminal? Here you will find some debate. Some say that the admonition in Matthew 5:38-48 to love our enemies and to turn our cheeks prohibits the taking of life, even in self defense. In my opinion, to make this an outright command against defending oneself under any and all situations is to take too much from this passage. Most Christians, and I will count myself among them, will say that the principle of loving our enemy, praying for them and even at times letting them abuse us, is not an absolute prohibition of self defense. So, I personally believe that there are extreme circumstances under which a Christian can take a life to save the life of an innocent person.