Human beings are self-justifying machines. We get it from Adam ("The woman you gave me . . ."). It's not a noble trait. Part of the fallout from our desperate desire to justify ourselves is that it causes us to judge others without being willing to judge ourselves. Quick to point out the speck in our brother's eye, we cannot see for the log in our own. Self-justification is fueled all the more when the speck in the other's eye is truly as big as a log, making our log seem like a speck. This was the problem that Simon the Pharisee had when a woman, whose "sins were many," came uninvited into his home (Luke 7:36-50). He had every reason to think she was "a sinful woman," but her overt sinfulness allowed him to think more highly of himself than he had a right to do. In fact, he thought so well of himself that he stood in judgment over the One before whom all will give an account, including Simon. That will not be a pretty day for the Pharisee, unless at some point, by the grace of God, he came to see that his need for forgiveness was as great as the woman he despised.
Self-justification has no place in the life of a Christian. We, of all people, should recognize that we are doing better than we deserve. In light of the reality that Christ died for us "while we were still sinners" (Romans 5:8), an act that one would scarcely do for a righteous person, we have every reason to be as grateful as the unnamed woman who wept at Jesus' feet. Yet, we are prone to slipping into the same mindset as Simon. When that happens remember how Jesus responded to the Pharisee. The parable he offered Simon was a devastating critique of the man's attitude. He didn't get it, but we should.
A helpful antidote to the poison of self-justification is a resolution Jonathan Edwards penned when a young man: "Resolved, to act, in all respects, both speaking and doing, as if nobody had been so vile as I, and as if I had committed the same sins, or had the same infirmities or failings as others; and that I will let the knowledge of their failings promote nothing but shame in myself, and prove only an occasion of my confessing my own sins and misery to God." Joining Edwards in his resolve could go a long way in drying up the fuel that runs our self-justifying machine.