There are two stories at the start of Luke 18. The first (1-8) is the story of the woman who plagued an unjust judge until he vindicated her. The second (9-14) is the story of the two men who went to pray at the Temple: in a surprising reversal, designed to shock the self-righteous, Jesus says it was the miserable sinner who went home justified, and not the religious Pharisee.
I can’t speak for every preacher, but it’s tempting to treat them separately. I’ve preached several times on the second story (you can read some of my thoughts on it here).
But we shouldn’t miss the connections between them.
Both stories are about prayer. The first is told in order to encourage perseverance in prayer. Jesus suggests that the problem is not so much that God is reluctant to answer, but that his followers’ faith lacks perseverance. The second is told in order to discourage self-righteousness. Of course self-righteousness is an unedifying business whether it seeps through in prayer or simply in everyday attitudes. But its folly is presented to us in a story about prayer.
Both stories are about ‘rightness’. The woman in the first story is looking for the judge to avenge her against an opponent in law. The second story is about which of the two men at prayer are justified. It’s easy to miss in our translations, but vindicate/avenge/righteous/justify are all connected linguistically in Greek. In the first story, the woman is vindicated by the judge who is forced to recognise the rightness of her cause; in the second story, it is the man who has no claims of his own rightness who ends up being justified while the man who attempted to justify himself (parade his own righteousness) was brought down.