Two men went to pray, Jesus said in this parable: a socially respected religious leader, and a socially despised tax collector (Luke 18:10).  As the Pharisee prayed, he boasted of his religious superiority (Luke 18:11-12): but the fraudulent tax collector admitted his unworthiness and simply asked for mercy.  There was no pretence or bravado, no excuses or 'special pleading' before God.  He knew there was no hiding place for his sin, which he admitted as he asked for mercy, like the penitent thief on the cross (Luke 23:40-43).

Neither the Pharisee nor the tax collector joined the crowd of worshippers.  The religious man stood by himself so that he could be observed to be different, because of his supposed holiness (Luke 18:11).  The corrupt civil servant would not go near the worshippers.  He only wanted his heart to be known by God.  He could make no show of holiness, his honesty overcame his guilt and he pleaded for mercy (Psalm 51:1-2).  His prayer, unlike the Pharisee’s, was heard.

Jesus' summary would have been shocking to His God-fearing audience.  He said that the dishonest civil servant was accepted by God, but the Pharisee was not!  All the religious law-keeping counted for nothing, and the boasting did not impress God at all.  But simple honesty, a humble admission of sin and a plea for mercy was just what God was looking for.  The difference between the men was not in their religious enthusiasm (for undoubtedly the Pharisee had much more zeal), but in their honest assessment of both themselves and God.  The Pharisee thought he could impress God with his boasting; the tax collector knew that he could not fool God.

Jesus said that humility is a choice which the tax man made, and the Pharisee did not.  It is a conscious decision to admit that we are wrong about pretending to be better than we are; and wrong to think that God is deceived by our religious attempts to show how good we are.  Humility accepts that God is always right, and we are not.  Humility accepts that our sin is a problem to God and that only His mercy can deliver us from His wrath.  So, to humble ourselves is the most important thing we can ever do; it comes before repentance and leads to reconciliation and peace with God. Yet it is the most difficult thing to do because it goes against our self-centred nature. But when people accept God's revelation of Himself, the offensiveness of their sin and the offer of mercy in the gospel - then they can humble themselves and allow God to save them through the sacrifice of Jesus Christ.  1 Peter 5:6 says, "Humble yourselves, therefore, under God’s mighty hand, that he may lift you up in due time."  It is the essential mark of Christian discipleship!