When I think of ‘man’s righteousness being as filthy rags', I contemplate it in this fashion: To imagine that I can please God to the point of being accepted by Him by my offered works, is like being a pauper, clothed in filthy, putrid garments; and the King, immaculately dressed from head to toe in rich clothing, and seated upon His white, unblemished horse, calls me over into the road to have a word with Him; and, as we are speaking, He sniffles as though in need of a towel to possibly sneeze in, and I, arrogant fool that I am, take from my ragged pocket a soiled and spotted rag, and present it to Him; just like unworthy Uzziah who thought his unholy hands were in any way fit to assist the Holy Ark of God. Nevertheless, as if what I had done is not bad enough, after He has looked with disgust upon my offer and flatly rejected it, I insist that there are some spots on the rag that do not appear to be soiled, with which He may wipe His face if He only holds it a certain way; as though my untrained eyes, accustomed to seeing so much filth, could ever accurately discern what is truly soiled and unsoiled; could have ever beheld something in my sphere that was actually pure! Oh, what a fool and what an arrogant insulting fool I would be to do this. It is of course good for me to have that inadequate rag and to use it habitually on myself: it demonstrates my desire to be clean, though, miserable pauper that I am, I entirely lack the means to ever make myself fully clean, or truly clean in any manner whatsoever by its routine use. Only by the King's decree, by His Word alone, can I be made completely clean and be given new garments and a more dignified rank and occupation that will not soil me again. But for those of my impoverished sort and on my lowly level to willfully forsake the use of a measley rag; well, what can that mean but that these people have embraced their filth?--and what would such as they know about desiring the King's cleanliness, upon Him offering it to them? Even among such a poor and dirty demographic, as I have described, a distinction would naturally be drawn, recognizing those who use a rag to regularly wipe themselves as being “clean” and those who forsake such a rag as being “dirty”; for what is righteousness but moral cleanliness, and wickedness but moral filthiness?  No: such as belong to the latter designation will scoff and coldly reject the King’s Offer, as demonstrated by their maintained rejection of the mere rag, because they love their filth; but this filthy sort would nevertheless love, all the same, to be invited into His heavenly palace, where they would immediately ransack that paradise and soil and stain all of its pristine perfection with their dirty selves; and would never willingly consent to being thrown into a hellish dungeon for the rest of their lives.  But that rag, nevertheless, is nothing, for those regarded among their impoverished peers as “clean”, to ever present to the King but an insult, and an enormous one at that; for both “clean” and “dirty” before the immaculate King are alike filthy and unworthy to stand in His Presence and to set foot upon His Holy ground.  And this is what those who TRUST in their works, and think to offer God their works for the Great Gift of Salvation, are doing. But that, of course, is their heart's issue, till God, hopefully, by His humbling Grace reveals Himself to them.  I hope this little analogy is a blessing.