This document discusses three reasons why Christians should not lose heart according to 2 Corinthians 4:16-18. First, we should value our inner spiritual being over our physical bodies which will decay. Second, we should value the eternal glory of heaven over temporary earthly troubles. And third, we should value the future promises of God over our present circumstances, because what we see on earth is temporary but God's promises are eternal. The document encourages readers to trust God's word, look to heavenly things, and fix their hope on the unseen eternal promises of God.