Old Testament Wars

Q: Why is there so much God-ordained bloodshed in the Old Testament, when we have the injunction, ‘Do not kill’?”
A: In Old Testament times we readily find that both defensive and offensive wars were sanctioned by the Lord. The following passages are just some examples of the way in which God gave his approval for the children of Israel to attack their heathen neighbors: Ex. 17:16, Num. 21:1 ff., Deut. 20:12, 19, 20, Josh. 11:6, 18. But it must be remembered that Israel, in Old Testament times, was a theocracy. This means that God himself gave direct orders to Israel in carrying out civilian and government affairs, even including whether or not Israel was to attack a neighboring country. When God established the Mosaic covenant with his Old Testament people, he let them know why he was commanding them to annihilate the heathen nations around them: “For you are a people holy to the Lord your God. The Lord your God has chosen you out of all the peoples on the face of the earth to be His people, His treasured possession,” (Deut, 7 6). Through Israel God would have the Messiah-Savior come, which would be a blessing for all nations, and therefore God’s Old Testament people had to be, preserved from outside, heathen influences. At the same time, we learn from Scripture that it was an act of patient wisdom on God’s part not to let Israel drive out the Canaanites at once, but only little by little (Ex. 23:28-30, Deut. 7:22).
But God still had given the enemies time to repent. For example, in the case of the Amorites, God gave them hundreds of years to repent, and yet they did not (Gen. 15:16). Noah preached 120 years to his generation prior to the Flood’s arrival (Gen. 6:3). So, the proper picture of God in Old Testament times is one who would give people untold opportunities to repent and believe in his gracious forgiveness. Yet, when they continually would refuse, he would judge and punish them for their evil deeds.
In the Apology of the Augsburg Confession, Luther and the Reformers recognized God’s sanction of this kind of bloodshed. The statement is made: “David’s labors in waging war and in governing the state are holy works, true sacrifices, battles of God to defend the people who had God’s Word against the devil, that the knowledge of God might not perish utterly from the earth” (Ap., Art. IV, par. 191).
Though we do not have a theocratic government in any part of the world today, all Christians still recognize that the Lord, while forbidding murder, has empowered and even commanded the established government to take the life of a person in punishment of a murder committed (Gen. 9:6, Matt. 26: 52, Rom. 13:4). There is no inconsistency with the Fifth Commandment, either in this matter of capital punishment; by the government today, or in the matter of the theocratically controlled wars of the past.