The God of the Bible is Bloodthirsty and Violent

If you've ever opened a Bible and read the Old Testament then it’s likely you've come across passages that are full of judgement and violence. God has been described by some as a bully in a playground who throws his weight around if he doesn't get his way. Are these ‘wars’ any different to ISIS and other extremist groups who use force to make you believe or murder you if you don’t? Does the God of the Old Testament really sanction war, violence and killing? How do we reconcile this with the words of Jesus who said ‘love your enemies’ not ‘kill them’?