Two prayers in the temple, and only one was heard.
Luke says who it was for before telling it: "certain people who were convinced of their own righteousness, and who despised all others". Two men go up to the temple. One is a Pharisee, respected for his devotion. The other is a tax collector, gathering taxes for Rome and despised by everyone.
The Pharisee prays at length about himself. The tax collector says one sentence.
But the tax collector, standing far away, wouldn't even lift up his eyes to heaven, but beat his breast, saying, 'God, be merciful to me, a sinner!'
The Pharisee is not lying. He fasts twice a week and tithes everything, as he says. The trouble is that his prayer is a comparison: he measures himself against the tax collector at the back and finds himself doing well. The tax collector compares himself with no one. He has nothing to present, and does not try.
Jesus says the tax collector "went down to his house justified rather than the other" (Luke 18:14). To his listeners this was a shocking reversal: the model of devotion leaves the temple with nothing, and the collaborator with the empire leaves right with God, on a one-line prayer.
The parable has a trap built in. It is easy to finish reading it thanking God you are not like the Pharisee — which is exactly the Pharisee's prayer. The point is not to pick the right character to look down on, but to stop praying with one eye on the person next to you.
Walking with Jesus has a collection called The Parables of Jesus that takes them one a day — each with the question he was answering, a short reflection, a prayer, and one thing to carry into the day.
It is a one-time purchase, about five minutes a morning, and it never asks you to catch up on days you missed.