D.A. Carson on the origin and varied manifestations of “self-justifcation”:
That sin goes back to the Garden, where Adam blames Eve and Eve blames Satan himself. It is difficult to think of any sin we commit that does not include a dollop of self-justification.
Jesus tells the parable of the Good Samaritan to a lawyer who asked a question because he ‘wanted to justify himself ’ [Luke 10:29].
Elsewhere he condemns the Pharisees because, he says, ‘You are the ones who justify yourselves in the eyes of others, but God knows your hearts. What people value highly is detestable in God’s sight’ [Luke 16:14-15]. The difference between the Pharisee and the tax collector lay in the fact that only one of the two was confident in his own righteousness [Luke 18:9].
In other words, self-justification wears many faces.
Like the lawyer in Luke 10, it may ask a slightly stupid and certainly morally vacuous question because one’s personal limitations have been exposed and one is trying to claw one’s way back to the top.
Like the Pharisee in Luke 18, it may pray with utterly unself-conscious arrogance and condescension.
Like those in Luke 16, it may prefer the approval of fellow human beings much more than the approval of God.
The common ingredient, self-justification, similarly lurks behind so many of our sins of pride, inverted or otherwise. And the biblical answer to self-justification, of course, is the justification we must have from outside ourselves, the justification only God can give. The more we succumb to the assorted convolutions fed by self-justification, the more our lives testify that we have not absorbed very well what it means to stand wholly justified before God on the sole ground of what Christ Jesus has borne on our behalf.