Man is not defiled by his impurities. It is the other man pointing out his impurities to him, whom he is defiled by. Is there anything anyone can do, to become righteous, anyway? God made us impure. If he had a problem with that, He would have made us gods, instead.
At such times, the heart of man turns instictively towards his Maker. In prosperity, and whenever there is nothing to injure or make him afraid, he remembers Him not, and is ready to defy Him; but place him in the midst of dangers, cut him off from human aid, let the grave open before him, then it is, in the time of his tribulation, that the scoffer and unbelieving man turns to God for help, feeling there is no other hope, or refuge, or safety, save in his protecting arm.