The 'life' which Jesus urges us to lose is the selfishness that lives within us, the old nature of sin that is in conflict with God. Matthew left the 'custom seat,' a political job, to follow Christ. So, in your life and in mine, 'self' must be crucified and Christ enthroned. He was intolerant of any other way, for He knew that selfishness and the Spirit of God cannot exist together. He was tolerant toward the sinner, but intolerant toward the evil which enslaves the sinner.
Sin lies at the root of most of society's difficulties today.
Whatever separates a person from God disunites that person from others. The world problem will never be solved until the question of sin is settled. But the Cross is God's answer to sin. Forest rangers know the value of the 'burn-back' in fighting forest fires. To save an area from uncontrolled fire, they carefully burn away the trees and shrubs to create a safety barrier.