Their problem was that they put their own brand on their acts of piety; they claimed their achievements for themselves rather than for God. Their righteousness and their holiness, they thought and taught, were self-generated rather than God-given. They were so full of themselves that they displaced God. They refused to acknowledge their dependence on God and his gracious provisions for them...This is why preaching that skirts the Law and preaches about the Gospel but does not actually preach the Gospel is disturbing. Preaching that vaguely alludes to sin but does not horrify us is dangerous. However, it does make sense that if the Law is not preached in its severity, there is no need for the eternal comfort of Christ's atoning sacrifice on the cross.
We face the same dangers in our spiritual lives. We quite readily imagine that we are actors performing before God to gain His applause rather than beggars receiving His gifts. Nothing excites us more than the desire to do something great, achieve something extraordinary. Of course, we don't do this for ourselves but only for God! Since we secretly admire those who seem to be spiritual superheroes, devotional highfliers, we focus on our spiritual performance and our religious achievements. We use God's gifts to gain spiritual kingship, power, and glory for ourselves, though we say we use them for God and the growth of the Church! We therefore become blind to the depths of our sin and the extent of God's grace. All too quickly our spirituality becomes an exercise in blatant self-deception and glossy self-promotion. We cover up before God and advertise ourselves as our own creation. We want the glory without the cross. We avoid full exposure to the scrutiny of God's Law; we belittle the call to repentance; we protect the old self from demolition and reconstruction by Christ. And all this because, like the Pharisees, we want to be seen to be holy, approved, admired, and praised by those around us, rather than by God."
That's why LCMS president, Matthew Harrison's insight on the importance of Law/Gospel preaching is important. "The Law should be preached like there is no Gospel and the Gospel should be preached like there is no Law."
What is the solution? Harrison, Kleinig and God's Word proffer the only solution to the damnation of our sin:
I want to hear declarative application that tells me my sins are forgiven right now and that I am directed to Christ and his comfort.
God always wants us to start where we are, rather than where we would like to be, on our spiritual journey. We are justified by God's grace and approved by Him. That's given! Our justification does not depend on our piety and our spiritual performance but on Christ and His performance. We can therefore face up to our recurring failure to live as His holy people and people of prayer. In fact, our failure is meant to teach us to ask for what we lack and receive everything from Christ.