War in the Bible

I want to discuss a common problem non-believers have about the Bible. This subject is seldom mentioned. It is the subject of how God goes to war when people worship false Gods. He is completely against sin and sin must be destroyed as it comes from the devil. Explaining this to non-believers is a big problem. They must realise that God only goes into battle as a last resort. I get the impression that He pleads and begs them to repent. Accounts of these wars is nasty and maybe needs a health warning. I get upset myself and have learned to skip any reference to war. It just has to be in the Bible as a history lesson. I get the impression that God does not want us to read too much of it as it is recitative. If you read of a war the next account of another war is very similar. I suppose the main message we need to get across to non-believers is that God is love, He loves all and wants everyone to believe in him. What do you think?