Earlier in 1 Corinthians Paul was dealing with unrighteousness, tolerance of sin and a lax attitude toward holiness, but now he turns his attention toward dealing with excessive self-righteousness. Legalism is subtle and can seem like holiness, but it is just as sinful as sexual immorality and other sins. Self-righteousness is born out of self-love and loathing of others — seeing other Christians as average, subpar and not pleasing to God. The legalistic believer is concerned more with performance and appearances — creating lists and rules of holiness that aren't found in the Bible. When we become self-righteous we depend more on our own performance and potential rather than Christ's finished work on the Cross. Trust in Jesus' cleansing blood. It is Christ, and Christ alone, that sets us free from our sin.