He sees the Law as nothing but the source of condemnation and death for the Christian, and it is not something that humans can harness for their use. Luther shares with Calvin the view of the total depravity of human beings who are unable to sanctify themselves (Gen 6:5, Jer 17:9, Rom 3:10).
All of the goodness that a Believer manifests comes through the divine work of the Holy Spirit. Luther poses all these truths through the Cross as the only way to comprehend God – as the Lamb who lays down His life, suffering the anguish of humiliation and death to ransom us back from the father of lies. Greater love has no one than to lay down His life for them, and Christ did so lovingly while we are still strangers and dead in our sin.
In contrast to the Cross, Luther describes a Theology of Glory who see human beings as merely weak in their sins, not entirely dead in them. Those of the Theology of Glory hold some optimism about their ability to work virtue in their lives apart from the Holy Spirit, and they believe that they can direct the Law to achieve on their own merit. Their arrogance extends to God whom they expect to see face to face as Moses did, still failing to understand that they cannot see God and live. They don't comprehend the profundity of what Christ did for them, expecting to walk into God's presence without that keen sense of who they are before a Holy God.
They use good works which are external acts, and they share that glory with God – the glory that the Reformation declares to belong to God alone. Luther contends that those who pursue their own glory declare the evil things in this life to be good, and they say that good is evil. Luther says that the Theology of the Cross states things as they actually are, and in so doing, the Cross proves to be the opposite.
Those who seek after Glory and not the Cross do things apart from the Holy Spirit (who only works through us from the inside out). We do all things in Christ; we are hidden with God in Christ, and in Him, we live, move, and have our being. They end up no different than those who seek to do God's good work apart from Him, but this is what makes the most sense to us in our fallen nature. It is only truly God's grace that changes us from the inside out after the King of the Universe declares us to be righteous in His sight in Christ.
Calvin put it this way: apart from the indwelling Spirit's work in the inner life of the Believer, Christ is only a “dead image” or a “corpse.” Luther calls them hirelings, and they slip away into doubt and false doctrine.