In response to the question, "What about the God of the Old Testament? He wasn't so 'peace and love'," Bono answers:
"There's nothing hippie about my picture of Christ. The Gospels paint a picture of a very demanding, sometimes divisive love, but love it is. I accept the Old Testament as more of an action movie: blood, car chases, evacuations, a lot of special effects, seas dividing, mass murder, adultery. The children of God are running amok, wayward. Maybe that's why they're so relatable. But the way we would see it, those of us who are trying to figure out our Christian conundrum,
is that the God of the Old Testament is like the journey from stern father to friend. When you're a child, you need clear directions and some strict rules, but with Christ, we have access to a one-to-one relationship, for, as in the Old Testament, it was more one of worship and awe, a vertical relationship. The New Testament , on the other hand, we look across at a Jesus who looks familiar, horizontal. The combination is what makes the cross."
(thanks to Snapshots from my World)