Christianity is not moralism. Christianity is not religiosity. Jesus was crucified because we are committed to saving ourselves by our religious stamina and moral efforts. The Beatitudes in their simplicity are not commands to be followed, principles to live by, or attitudes to adopt. They profile people who have crucified their own morality in Jesus' death, resurrection, and rule.
Crucifying Morality walks through Matthew 5:1-12, where Jesus doesn't prescribe what ought to be in order to experience God's grace, but describes what is true of people who understand the grace of God.