The word Propitiation is mentioned in the KJV three times. Looking at 1 John 2:2; 4:10 we see that Christ is said to be the propitiation for our sins. The Greek word for propitiation (hilasmos) means "that which propitiates". What does the word "Propitiation" mean? Propitiation is the turning away of wrath by an offering. It is satisfying the wrath of God by the sacrifice of Christ. We need to remember that propitiation is a two part act. It is satisfying the wrath of God and being reconciled to Him.
Let's look at a few passages that will shed some light on the use of the word "propitiation". Remember here that Romans 3:23 tells us that we have all sinned. Then Romans 6:23 gives us the penalty of that sin and says, "the wages of sin is death", referring to the second death which is eternal separation from God in a lake of fire. Christ is here called the propitiation for our sins and the reason is, He becomes our substitute and takes on the wages of our sin covering them by the punishment which He endured.
Romans 3:25 says, "Whom God hath set forth [to be] a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;" The word propitiation used here is the Greek word "hilasterion" and means the place of propitiation.
In Hebrews 8:12 it says, "For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more." The word "merciful" here is the Greek word hileos which would mean propitious. In Luke 18:13 it says, "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." The word "merciful" used here is the Greek word hilaskomai which would mean propitiated. Hebrews 9:5 says, "And over it the cherubims of glory shadowing the mercyseat; of which we cannot now speak particularly." The word mercyseat used here is the Greek word "hilasterion" is referring to the ancient tabernacle worship of Israel.
We need to go back to the Old Testament to understand propitiation. The Bible does this with many words. For example, in John 3:14 we can not understand the lifting up of the serpent in the wilderness and lifting up the Son of man without going back to the Old Testament and looking at Numbers 21:1-9.
The ark was a chest of acacia wood and the mercy seat was the lid or cover of the ark. The mercy seat was made of Gold which is the symbol of divine righteousness. There were two figures of the cherubim that had their wings extended over the mercy seat. Exodus 25:20 tells us that the cherubims shall stretch forth their wings covering the mercy seat and their faces shall look one to another. In Hebrew the mercy seat of the tabernacle worship was called the place of the covering and it was here that the sacrificial blood was sprinkled, Leviticus 16:14. It was there that the sprinkled blood covered the worshipers sins. It became the meeting place of God and sinful man, Exodus 25:22; Leviticus 16:2; Numbers 7:89.
Going back to the New Testament now and looking at Hebrews 4:16 it says, "Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need." For the believer it is Christ that is the propitiation, the mercy seat or throne of grace. Christ is the meeting place and the place of communion between God and sinful man. This is why Paul gave believer's Romans 8:33, "Who shall lay any thing to the charge of God's elect? [It is] God that justifieth." Christ is the mercy seat sprinkled with His own blood and put away sin by the sacrifice of Himself, Hebrews 9:26. He is a high priest of good things to come, Hebrews 9:11-12.
Propitiation is the Godward aspect of Christ's death that satisfies the demand of the law upon the sinner. This opens the way for God to meet, in Christ, (who is God's mercy seat) every sinner that believes. The law is God's expression of His holiness and the cross and expression of His love. For believer's, what would have become a judgment seat has become a mercy seat, a throne of grace.
Christ's saving work that delivers from God's wrath is His propitiation on the cross and is the only way to turn away God's divine condemnation of sin. For those that reject Christ as their savior there is no hope of salvation, John 14:6. Those that reject Christ can only look forward to the wrath of God that they have stored up for the day of judgment, Romans 2:5. No propitiation or sacrifice can be made for the sins of anyone that rejects Christ. They will spend eternity separated from God in a lake of fire, Revelation 20:14-15.