I've been in conversation with various war supporters over this whole preemptive invasion we've got happening in Iraq. As a pacifist, I am opposed to this invasion.
These conversations have been with individuals who identify themselves as Christians and have generally been theological in nature. All of these war supporters have agreed that Jesus certainly sounds pacifistic, but that they just can't get around that the God of the Old Testament did wage war. And, they say, God doesn't change.
I've been doing some research on this point and have responded to one of my war-supporting friends thusly:
It seems to me that if you want to argue the possibility of Christians supporting a military based on what the OT has to say, then you have to correctly recall what God had to say about the military in the OT.
Early on in the OT, you have God as sole deliverer. That is, God's people were in trouble and God saved them without any military support from the people.
As in the story of the flood.
[Now the earth was corrupt in God's sight and was full of violence. God saw how corrupt the earth had become, for all the people on earth had corrupted their ways. So God said to Noah, "I am going to put an end to all people, for the earth is filled with violence because of them...” Genesis 6]
As in the Exodus.
[I will sing to the LORD because HE has won a glorious victory; he has thrown the horse and the rider into the sea... Moses' song]
The concept of Israel wanting to depend upon kings and horses and chariots (military strength) and God rebuking Israel for these desires is repeated throughout the OT.
Later in the Bible (in Joshua, Judges...), you do have mixed situations of God winning the fight, but then Israel's army going in and mopping up (killing all survivors).
As in Joshua, as in Gideon, later on, as in David and Goliath.
You might be tempted to ask, "What changed? Before God wanted to be the deliverer and now God is willing to let an army do some of the work? Has God changed?" And I think that is a good question to ask. More on that later.
Throughout this time (Joshua and the settling of Israel, pre-Kings), you still have God telling Israel to not have a standing army, to not have the latest in weaponry (chariots and horses). God wanted Israel to trust in God, not its military. "I gave you the victory...your swords and bows had nothing to do with it." Joshua 24:11-12
When Israel began demanding a king, like all the other nations, God was opposed to the idea, knowing rightly that it would lead to Israel's trusting in its own power and not God. Samuel warned Israel that going the King route would result in a king that drafts their sons into a chariot army, that would make their children work for the king, that would tax them to support this military and royal infrastructure, but, as you know, the people persisted and God relented.
Did God relent because it was the right thing? Clearly not.
God warns in Deuteronomy: When you do get a king..."he shall not multiply horses for himself, nor cause the people to return to Egypt to multiply horses, for the Lord has said to you, "You shall not return that way again." Neither ... shall he greatly multiply silver and gold for himself.
In Deuteronomy, God goes on to say that "When you are in battle, and you see chariots and horses and are outnumbered, do not fear. I will be with you."
Despite these warnings and rules, the time of the Kings in Israel was the most war-torn period of the OT. And, it seems to me, this is exactly BECAUSE Israel was trusting in an army.
And so, for those who point to the OT as a reason for supporting our military, it seems to me that they're comparing apples and oranges.
Israel, when it was most right with God, had a small volunteer army only used for special occasions when God called for it.
We have the most massive military machine on earth.
Israel did not use the latest technology available.
We are always on the cutting edge of killing technology.
Israel was trusting in God to deliver.
We are clearly trusting in our military and hoping that God uses our military to deliver us.
The concept of God in the OT using an army or allowing an army to kill to further God's will (as in when Israel was overtaken by the evil Assyrian army) in no way endorses us taking part in such an army.
Or, at the most, you might stretch that to say that there are certain times when God has told some to go and kill the men, women and children of a kingdom; but if we were to consider doing so, well, we better be pretty damned sure that it's God speaking.
Myself, I don't see it happening.
I think of Isaiah, whom God had run around naked for three years. Does that mean you and I ought to be running aroung naked? No. That was a specific occasion called for by God. But our norm should be not running around nude.
As in nudity, so in war. As Christians, our norm must be Jesus, who taught us to love our enemies, to stand up to evil but turn the other cheek.
And you know, Jesus did reinterpret the law ("You have heard it said, 'an eye for an eye, a tooth for a tooth,' but I tell you to turn the other cheek...You have heard it said, 'Hate your enemies,' but I tell you: Love your enemies, do good to those who hate you.")
Does that mean that Jesus thought God had changed? No, but it could mean that people were wrong in their interpretation of what God had done. Or simply that Jesus had an even better teaching from God. Regardless, this is a definite change from Old to New Testament.
Maybe there would come a time where God would call us to do something (like kill) that is so completely far outside the norm of Jesus, but that would be the exception rather than the rule and even then, we must trust in God to do the delivering and not a military.
In short, I might concede the concept of an army based on the OT, but only if said military is done in an OT manner:
1. volunteer army amassed in time of crisis
2. only when God has told us to
3. without all the latest military weaponry and
4. without the HUGE drain on the budget that accompanies disobeying the first three rules
Actually, upon thinking about it, I probably would concede the concept of such an army.
I've tried to construct this argument in terms that someone concerned with reconciling the tension between the Old and New Testaments in regards to violence would feel comfortable with. I hope you find it compelling and, should I be right, that God might convict and change your heart and mind on these points, friend.