He also told this parable to some who trusted in themselves that they were righteous, and treated others with contempt: "Two men went up into the temple to pray, one a Pharisee and the other a tax collector. The Pharisee, standing by himself, prayed thus: 'God, I thank you that I am not like other men, extortioners, unjust, adulterers, or even like this tax collector. I fast twice a week; I give tithes of all that I get.' But the tax collector, standing far off, would not even lift up his eyes to heaven, but beat his breast, saying, 'God, be merciful to me, a sinner!' I tell you, this man went down to his house justified, rather than the other. For everyone who exalts himself will be humbled, but the one who humbles himself will be exalted." (Luke 18:9-14)
Take a look at the Pharisee. He is completely out of touch with what he really is. He frantically avoids the haunting conclusion of being flawed and sinful and not-so-great by employing three ways to dodge the bullet and exalt himself: seeking glory and attention by making a spectacle of himself in front of others, pointing to his performance, and comparing himself to others. He is inwardly and upwardly dull but hopelessly focused on externals. Do you do these things?
These are all the things that I do. And because of it, I am up-tight, I can't take criticism, I have thin-skin, I am moved to aggress against myself when I fail or compare poorly to others, and I get easily angered when someone else compares me to others or puts me down. And what happens when I actually think I'm pulling it off? What happens when I compare well to others and get the recognition I think I deserve? I treat others who do not do so well with contempt. Isn't it funny how insecurity and arrogant self-righteousness are often two points on the same continuum? What an exhausting way to live. Trying to prove that you are pretty good by your own efforts and in relation to other people is a full-time job.
Now, look at the tax collector. He is completely in-touch with what he really is. He is inwardly and upwardly focused and externals aren't even important enough to him to come into the picture. What owns him is his sinfulness and need for God’s mercy, and Jesus tells us that he goes home having it. He goes home justified, right, righteous. He knows he is a sinner -not merely as a religious concept but as a personal reality. And he therefore experiences God's mercy in the same way.
Every Christian "knows" he is a sinner. Some of us have truly sordid pasts. But do you know you are a sinner? Do you know you are still a sinner? Do you know it like the tax collector? Do you really get that you can contribute nothing to your righteousness? Has it humbled you? You will know you are truly humbled, you will know you really know you are sinner, when you no longer rage against that haunting conclusion about yourself and no longer try to defend yourself from it or distract yourself, God, and others away from it. As it says in Romans 3, your mouth is "stopped," inside and out.
Notice the result of having a stopped-mouth. He comes knowing he needs mercy, and he goes home having it. "God opposes the proud, but gives grace to the humble."
"For there is no middle ground between Christian righteousness and works-righteousness. There is no alternative to Christian righteousness but works-righteousness. If you do not build your confidence on the work of Christ you must build your confidence on your own work." ~Martin Luther