Jeremiah17:9

"Christian know that the closer they get to God, the more they become aware of their own sin. In this the saint is rather like the scientist. The more scientists find out, the more they realize how little they know and how much there is still to discover. Similarly, the more Christians grow in their imitation of Christ, the more aware they become of the vast distance which still seperates them from him.

A glance into any Christian biography underlines this - if our own experience is not sufficient evidence. Let me offer just one example. David Brainerd was a young pioneer missionary among the Indians of Delaware at the beginning of the nineteenth century. His diary and letters reveal the rich quality of devotion to Christ. Despite the great pain and crippling weakness, which led to his death at the age of twenty-nine, he gave himself totally to his work. He travelled on hourseback through thick forests, preached and taught without rest, slept in the open and was content to have no settled home or family life. His dairy is full of expressions of love to 'my dear Indians' and of prayers and praises to his Savior.

We might imagine that he is a saint of the first order. Surely his life and work can't have been unduly tainted by sin. Yet as we turn the pages of his diary, he continually laments what he describes as his moral 'corruption'. He complains of his lack of prayer and the poverty of his love for Christ. He calls himself 'a poor worm' and 'a dead dog', and 'an unspeakably worthless wretch'. This not because he had a morbid conscience. It was the closeness of his relationship with Christ that made him so painfully aware of his sinfulness"

John Stott, Basic Christianity - pg52-53.

God, you know how filthyi am. sometimes i dont even know how to come to you. i can only hide behind Jesus and cry have mercy on me, for i am a sinner.