Double Unrighteousness

To see to be justified by the Law is as a if a man, already weak and ill, were to go in search of some other greater evil whereby he hoped to cure his ailment, whereas it would of course, bring him utter ruin, as if a man affected with epilepsy were to add the pestilence to it, or as if a leper were to come to another leper or a beggar to a beggar  so that the one might help and enrich the other.  Here, as the proverb puts it, one milks the ram while the other holds the sieve under him....  The Gospel bears witness to the same truth when it speaks of the woman who for twelve years had an issue of blood and suffered many things from many doctors and had spent all she had and yet could not be cured but rather became worse the more they tried to cure her (Mark 5:25ff.).  Therefore, as many as do the works of the Law with the intention of thereby justifying themselves not only are not made righteous but are rendered doubly unrighteous. 

Source: Quoted in Ewald M. Plass, What Luther Says, A Practical In-home Theology for the Active Christian. St. Louis: Concordia Publishing House. 1959 Edition, 10th Printing (1994), p. 711.