The Pharisees were the most religious people in Israel, but it was all hypocritical pretense, an outward show which displayed an obvious "holier-than-thou" attitude toward everyone else.
In the parable recorded in Luke 18:9-14, the Lord Jesus contrasted the self-righteous prayer of the PHARISEE with that of the prayer of the penitent PUBLICAN--a despised TAX COLLECTOR, a group of people who were prosperous because they cheated others in collecting taxes--who was bowed down with a sense of his own guilt before a holy God and was pleading for mercy:
LUKE 18:9-14
[9] And he spoke this parable unto certain which trusted in themselves that they were righteous, and despised others:
[10] Two men went up into the temple to pray; the one a Pharisee, and the other a publican.
[11] The Pharisee stood and prayed thus with himself, God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers, or even as this publican.
[12] I fast twice in the week, I give tithes of all that I possess.
[13] And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying, GOD BE MERCIFUL TO ME A SINNER.
[14] I tell you, this man went down to his house JUSTIFIED rather than the other: for everyone that exalteth himself shall be abased; and he that humbleth himself shall be exalted.
In this parable, the publican--in his penitent plea for MERCY--was portrayed by Christ as pleading to God to be "PROPITIOUS" toward himself a guilty sinner, based upon the open display of the BLOODY SACRIFICIAL LAMB in the temple, which was an Old Testament type or shadow of "CHRIST CRUCIFIED." We know that is true because the Greek word translated "MERCIFUL" in this parable is also translated "PROPITIATION" in other places in the New Testament (for examples, see 1 John 4:10 and Romans 3:25). Click on the link below for a Biblical definition of the word "propitiation":
https://www.angelfire.com/va/sovereigngrace/propitiation.html
Since the Lord Jesus used the word "PROPITIATION" in the penitent publican's plea for MERCY in this parable, we may safely conclude that He is making a clear reference to His own predicted substitutionary blood atonement when He was to die in behalf of guilty sinners on Calvary's cross (see 1 John 4:9-10), as the spotless LAMB OF GOD (see John 1:29).
What the penitent publican was actually saying was, "GOD BE PROPITIOUS TOWARD ME, THE SINNER."
At this point, a quote from C. H. Spurgeon is appropriate:
"There is one other feature in this man's prayer, which you must not overlook. What reason had he to expect that God would have any mercy upon him? The Greek explains more to us than the English does, and the original word here might be translated—"God be propitiated to me a sinner." There is in the Greek word a distinct reference to the doctrine of atonement. It is not the Unitarian's prayer—"God be merciful to me," it is more than that—it is the Christian's prayer, "God be propitiated towards me, a sinner." There is, I repeat it, a distinct appeal to the atonement and the mercy-seat in this short prayer, Friend, if we would come before God with our confessions, we must take care that we plead the blood of Christ. There is no hope for a poor sinner apart from the cross of Jesus. We may cry, "God be merciful to me," but the prayer can never be answered apart from the victim offered, the Lamb slain from before the foundation of the world. When thou hast thine eye upon the mercy-seat, take care to have thine eye upon the cross too. Remember that the cross is, after all "the mercy seat; that mercy never was enthroned, until she did hang upon the cross crowned with thorns. If thou wouldst find pardon, go to dark Gethsemane, and see thy Redeemer sweating, in deep anguish, gouts of gore. If thou wouldst have peace of conscience, go to Gabbatha, the pavement, and see thy Saviour's back flooded with a stream of blood. If thou wouldst have the last best rest to thy conscience, go to Golgotha; see the murdered victim as he hangs upon the cross, with hands and feet and side all pierced, as every wound is gaping wide with misery extreme. There can be no hope for mercy apart from the victim offered—even Jesus Christ the Son of God. Oh, come; let us one and all approach the mercy-seat, and plead the blood. Let us each go and say, "Father, I have sinned; but have mercy upon me, through thy Son." Come, drunkard, give me thy hand; we will go together. Harlot, give me thy hand too; and let us likewise approach the throne. And you, professing Christians, come ye also, be not ashamed of your company. Let us come before his presence with many tears, none of us accusing our fellows, but each one accusing himself; and let us plead the blood of Jesus Christ, which speaketh peace and pardon to every troubled conscience."—Confession and Absolution, a sermon on Luke 18:13 by C. H. Spurgeon
In the conclusion of this parable, the Lord Jesus said that the penitent publican left the temple and "went down to his house JUSTIFIED," rather than the boastful Pharisee, who obviously remained "UNJUSTIFIED."
The REAL KEY to understanding this parable lies in the meaning of the word "JUSTIFIED." Click on the link below for a Biblical definition of JUSTIFICATION:
https://www.angelfire.com/va/sovereigngrace/justify.html
The lesson that Christ would have us to learn from this parable is in the concluding sentence:
"Everyone that EXALTHETH HIMSELF shall be abased; and he that HUMBLETH HIMSELF shall be exalted."
In other words, those who BOAST and TRUST in their own righteousness will be ABASED in the condemnation of eternal judgment in HELL ("UNJUSTIFIED, guilty before God"), while those who HUMBLE THEMSELVES and PLEAD FOR MERCY on the basis of the PROPITIATON of the shed blood of the Lord Jesus Christ shall be "JUSTIFIED, declared righteous before God" or EXALTED TO ETERNAL LIFE IN HEAVEN.
[ Click Here to listen to Pastor John MacArthur's message, "Justification and Atonement"....fast-forward to 43 minutes into the sermon for the definition of "mercy" from the Greek.]