Being the daughter of a third generation Marine (my Grandfather and Great Grandfather have fought in wars.  In fact, the only reason my father was not sent into Desert Storm, as my best friend’s father was, is because of my impending birth, but that is a very long story for another time.  God was good.) I have heard many arguments made by Christians and none Christians alike about the rightness or wrongness of the wars fought.  Either people believe that “if we would all just be friends and put aside our differences, we would live in peace”, or the scripture “love your enemy and turn the other cheek” is used.  But what does the Bible really say about war?  What does it say about the role of soldiers and how they can reconcile taking the lives of other humans in that role?  Well, let’s look at a few verses.
Just like everything else in scripture, it all goes back to Genesis.  When God created the earth and put man upon it, He pronounced that it was all good.  That is until man sinned. Because mankind chooses to disobey God, we now live in an environment where evil men and good men are at war. God hates war; however, it is necessary to maintain order in the earth and overcome those who would like to destroy good. In fact, the first war ever recorded was the war in heaven where Satan and a third of the angels fought against God and his angels. We also know this war will ultimately be won, by God, through Christ.
Quote:
Revelation 12:7-11:
7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,8 And prevailed not; neither was their place found any more in heaven.  9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him. 10 And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night. 11 And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.
Now, it is important, when starting off on this discussion, to mention the fact that God sanctions government authorities to enforce laws.  Whether you want to look at the battles fought by the Scottish Covenanters, The Vietnam war, the World Wars, Desert Storm, or even the current war we face now, the fact remains that Christians have had to make the decision to defend and protect their loved ones (which includes the freedom of their loved ones) from generation to generation, be that on a large or small scale.  And the Bible is not silent about this subject, as it warns us that evil and war will increase more and more as the time for Christ's second coming approaches. 
Quote:
Matthew 24:6-8:
6 And ye shall hear of wars and rumours of wars: see that ye be not troubled: for all these things must come to pass, but the end is not yet. 7 For nation shall rise against nation, and kingdom against kingdom: and there shall be famines, and pestilences, and earthquakes, in divers places.
8 All these are the beginning of sorrows.
God set boundaries on mankind by establishing ruling authorities that would make and enforce the laws He gave. The purpose for this was because He knew unregenerate society, without any restraints, would seek to destroy good men.  Where we find most of people’s problems with the military action of our government, versus loving our enemies, is that God's law of justice for the taking of a life demands that a life be taken; yet, God's spiritual law of mercy and forgiveness grants that a murderer can be forgiven and restored. How can we reconcile this?  Is it a biblical contradiction?
 We must understand that God instituted civil authorities to maintain order in the earth. God uses them to restrain evil and they should be obeyed for this purpose.  Civil authorities are in place to maintain order in the earth. In the New Testament we see that even Jesus surrendered to the governing authorities because He was submitting to the Father's will. 
Quote:
John 19:11: "Jesus answered, Thou couldest have no power at all against me, except it were given thee from above..."
Quote:
Romans 13:1-5:
13 Every [a] person is to be in subjection to the governing authorities. For there is no authority except [b]from God, and those which exist are established by God. 2 Therefore [c]whoever resists authority has opposed the ordinance of God; and they who have opposed will receive condemnation upon themselves. 3 For rulers are not a cause of fear for [d]good behavior, but for evil. Do you want to have no fear of authority? Do what is good and you will have praise from the same; 4 for it is a minister of God to you for good. But if you do what is evil, be afraid; for it does not bear the sword for nothing; for it is a minister of God, an avenger who brings wrath on the one who practices evil. 5 Therefore it is necessary to be in subjection, not only because of wrath, but also for conscience’ sake.
From these verses we see that governments can elect to bear the sword (go to war) to deal with evil men. Although the act of war is a harsh form of punishment upon evil invaders, the alternative is far worse -- the destruction of innocent people by wicked aggressors. 
No soldier who is a Christian desires to kill another; however, the Lord Himself did not chastise a Centurion soldier in the Bible in the matter of his occupation. On the contrary, the Lord commended this man for his great faith when he called upon the Lord to heal his servant.  If he was in sin, do you think the Lord would really have set him up as an example not opnly to the people present, but to all of us who would read of his faith years later?
Quote:
Matthew 8:5-10:
5 And when Jesus was entered into Capernaum, there came unto him a centurion, beseeching him, 6 And saying, Lord, my servant lieth at home sick of the palsy, grievously tormented. 7 And Jesus saith unto him, I will come and heal him. 8 The centurion answered and said, Lord, I am not worthy that thou shouldest come under my roof: but speak the word only, and my servant shall be healed. 9 For I am a man under authority, having soldiers under me: and I say to this man, Go, and he goeth; and to another, Come, and he cometh; and to my servant, Do this, and he doeth it. 10 When Jesus heard it, he marvelled, and said to them that followed, Verily I say unto you, I have not found so great faith, no, not in Israel. 1 Timothy 2:1-6: 1 I exhort therefore, that, first of all, supplications, prayers, intercessions, and giving of thanks, be made for all men; 2 For kings, and for all that are in authority; that we may lead a quiet and peaceable life in all godliness and honesty. 3 For this is good and acceptable in the sight of God our Saviour; 4 Who will have all men to be saved, and to come unto the knowledge of the truth. 5 For there is one God, and one mediator between God and men, the man Christ Jesus; 6 Who gave himself a ransom for all, to be testified in due time.
Our military men need our prayers and the protection of the Lord as they go to battle.  They fight to keep us safe from harm.  They fight so that no daughter must be abused by the hands of evil men.  They fight so that evil men cannot strap a bomb to a child and use them to kill those who stand in their way.  They fight so that their sons will have the ability to raise their families as they see fit.
This should be the work of the church -- prayer for our men's protection and prayer for the heads of state (to be honest, I don’t care if you don’t agree with them, you can still pray for them because of the great power they hold over the people, including your family). Prayer is powerful.  We should pray that war would end as quickly as possible.  In fact, we should love our enemies enough to pray for them that they might be saved. We can pray that good will come out of what others mean for evil (Joseph anyone?).
Now, another thing that has to be looked at in this discussion is what the biblical definition of murder is.
When we look at the Ten Commandments listed in Exodus 20:1-17, we find the command  "Thou shalt not commit murder", in verse 13.  Now, many people find this a contradiction, especially when God has decreed that governments could send men to war to kill other men. The reason is because murder is very different than killing.  To murder means “to slay someone in a violent manner unjustly." So, unjust, premeditated killing with the wrong motives of hatred, vengeance, greed, jealousy, etc., is murder. Killing in self defense to protect oneself is not murder nor is executing condemned killers. The very founders of our nation were known to carry a Bible in one hand and a musket in the other in order to defend the freedom they sought here. The freedom to worship God was one of those freedoms they fought for and died for. 
That’s all I’m going to go into on the murder topic, since I have a very long winded discussion about murder vrs killing in the self defense thread.  Or you can find my thoughts on murder vrs killing on my blog.
Now, it is also poignant to point out that God didn’t just leave it at “governments have the right to go to war”.  He also spoke of military codes and conduct in the Bible.  
In the Old Testament we find  guidelines about military conduct.  In fact, unbeknownst to some, many of the regulations used in the US armed forces come directly from the Bible. The instructions given in regard to the battles of Israel are examples that were used to help establish our military so long ago.  The Israelites of old had much experience in battle, as throughout their existence, there were but brief intervals when they were not either engaged in war or in danger of it. Listed below are some of the rules given to them regarding military conduct and instruction: 
1.) AGE AND QUALIFICATIONS: First they were to take a census of the families indicating that there would be some discernment used in the selection of the males as they were numbered. The enlisting was spread across all the tribes.  They were drafted, so that all would share in the burden of war. They had to be males at least 20 years of age and up and all must be physically fit. In fact, those who were mentally and emotionally weak or cowardly were not to be enlisted. They selected men of valor, as they wanted a group of men to be examples to the others and they wanted all to have a sense of national patriotism.
Quote:
Numbers 1:2-4:
2 “ Take a [a]census of all the congregation of the sons of Israel, by their families, by their fathers’ households, according to the number of names, every male, head by head 3 from twenty years old and upward, whoever is able to go out to war in Israel, you and Aaron shall [b]number them by their armies. 4 With you, moreover, there shall be a man of each tribe, each one head of his father’s household.
Quote:
Deuteronomy 20:8
8 And the officers shall speak further unto the people, and they shall say, What man is there that is fearful and fainthearted? let him go and return unto his house, lest his brethren's heart faint as well as his heart.
2.) TRAINING AND PAY: All of Israel were liable to be called into active service to play the part assigned to them in furthering God's righteous cause. They were trained and paid for their duties and their needs of maintenance were met. Good officers and captains were chosen to lead the soldiers. 
Quote:
2 Chronicles 25:5-6:
Moreover Amaziah gathered Judah together, and made them captains over thousands, and captains over hundreds, according to the houses of their fathers, throughout all Judah and Benjamin: and he numbered them from twenty years old and above, and found them three hundred thousand choice men, able to go forth to war, that could handle spear and shield. 6 He hired also an hundred thousand mighty men of valor out of Israel for an hundred talents of silver.
Quote:
Deuteronomy 20:9: 
9 And it shall be, when the officers have made an end of speaking unto the people, that they shall make captains of the armies to lead the people.
3.) CHAPLAINS IN MINISTRY: Those who were priests (today, those who would be in ministry as chaplains) were not used in combat. They were to be available as ministers to stand and pray before the Lord for the soldiers and the battle. 
Quote:
Numbers 1:47: 
47 But the Levites after the tribe of their fathers were not numbered among them.
4.) EXEMPTIONS TO MILITARY DUTY: The Old Testament listed some reasons that males should be excused from military duty. They are as follows:
a.) Those who have just moved into a new home and haven't had time to live in yet.
Quote:
 Deuteronomy 20:5: "And the officers shall speak unto the people, saying, What man is there that hath built a new house, and hath not dedicated it? let him go and return to his house, lest he die in the battle, and another man dedicate it."
b.) Those that have just started a new business and have not yet had time to receive a return on it. 
Quote:
Deuteronomy 20:6: "And what man is he that hath planted a vineyard, and hath not yet eaten of it? let him also go and return unto his house, lest he die in the battle, and another man eat of it."
c.) Those that are engaged to be married were not to go to battle. 
Quote:
Deuteronomy 20:7 "And what man is there that hath betrothed a wife, and hath not taken her? let him go and return unto his house, lest he die in the battle, and another man take her."
d.) If a man has just gotten married when war breaks out, he is not to go to war for a year. 
Quote:
Deuteronomy 24:5 When a man hath taken a new wife, he shall not go out to war, neither shall he be charged with any business: but he shall be free at home one year, and shall cheer up his wife which he hath taken.
5.) BATTLEFIELD INSTRUCTIONS: In the Bible there are instructions about treating prisoners humanely, not violating women and children, caring for the civilian populace, relieving wounded soldiers, not destroying the conquered land, etc. Godly morals were to be the code in all of these instances. For example, they were told to enjoy the fruit of the trees of the conquered land, but not to destroy the trees themselves.
Quote:
Deuteronomy 20:19: When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by forcing an ax against them: for thou mayest eat of them, and thou shalt not cut them down (for the tree of the field is man's life) to employ them in the siege.
The Bible even records personal hygiene instructions on the battle field. 
Quote:
Deuteronomy 23:12-13: 
12 You shall have a place also outside the camp to which you shall go; 13 and you shall have a paddle or shovel among your weapons, and when you sit down outside, you shall dig a hole with it, and turn back and cover up your excrement.
6.) RULES OF ENGAGEMENT: The first thing, before attacking a city, the Israelites were commanded to do was to try to make peace with the enemy. If the enemy refused the conditions of peace, then they were to attack. 
Quote:
Deuteronomy 20:10-12:
10 When thou comest nigh unto a city to fight against it, then proclaim peace unto it. 11 And it shall be, if it make thee answer of peace, and open unto thee, then it shall be, that all the people that is found therein shall be tributaries unto thee, and they shall serve thee. 12 And if it will make no peace with thee, but will make war against thee, then thou shalt besiege it.
As to the extermination of foes, Israel had to remember that punitive war was in the interests of religion and morality and therefore her soldiers were to act, not as murderers, but as God-appointed executioners of divine judgment upon gross idolatry and iniquity (Deuteronomy 7). War was to be viewed as divine surgery for the cutting off of evil wickedness that would defile the rest of the world. God still uses nations today to execute wrath on evil.
Now, I have to sit down and do some other things for the forum before I sit down to write tonight, so I need to wrap this topic up.  In closing, though, I'd like to leave you with this verse. 
Quote:
Ecclesiastes 3:1-8:
There is an appointed time for everything. And there is a time for every event under heaven— 2 A time to give birth and a time to die; A time to plant and a time to uproot what is planted. 3 A time to kill and a time to heal;
A time to tear down and a time to build up. 4 A time to weep and a time to laugh; A time to mourn and a time to dance. 5 A time to throw stones and a time to gather stones; A time to embrace and a time to shun embracing. 6 A time to search and a time to give up as lost; A time to keep and a time to  throw away. 7 A time to tear apart and a time to sew together; A time to be silent and a time to speak. 8 A time to love and a time to hate; A time for war and a time for peace.
Hope that wasn’t confusing.  I was rushing a bit to get it written.