Scripture advises that anger clouds our vision and hardens our hearts. It makes us base rather than noble. It blinds us to our own failings and encourages a dangerous arrogance. It makes us forget we need forgiveness as individuals and as a nation.
It may well be true that "Forgiveness sets you free." However, the idea of forgiveness as a psychological or emotional condition traces to 18th-century moral philosophy, not first-century Christian writings.
The Bible says: The angels will come out and separate the evil from the righteous and throw them into the furnace of fire. If there's a candidate for most likely to be thrown in, shouldn't it be Anders Breivik?