The two men in the parable are socially and religiously at the opposite poles of Judaism. One is a Jewish religious leader, a Pharisee, and the other is a tax collector.
The Pharisee’s prayer is an exercise in self-congratulation. The tax collector is even hesitant to approach the sanctuary. He stands “far off,” and will not even lift his eyes heavenward.
So profound is his guilt that he beats his breast and says, “God, be merciful to me a sinner!” This poor man recognizes that his only hope is God’s mercy.
It should be obvious to us which one went home justified.