Propitiation (ἱλάσκομαι) is the act of making compensation, thereby providing a satisfaction. In the Old Testament, propitiation is found in the place between the cherubs on the Ark of the Covenant. The place of propitiation (ἱλαστήριον).
God set forth Christ as a propitiation through His blood to demonstrate His righteousness in the deferring of punishment for previously committed sins, Romans 3:25. Therefore, we are justified out from faith through grace, not through works, because Christ’s death for sin satisfies the righteousness of God in forgiving sins, Romans 3:24. Christ’s propitiatory work not only atones for the sins of those who are saved, but the entire world, 1 John 2:2. Therefore, God is just in permitting unrighteous beings into His presence while He demonstrates an aspect of His character to the spirit beings.
The Apostle John writes that God loved the world in this way, He gave His unique one-of-a-kind Son so that all the ones believing in Him would be saved, John 3:16. His Son made a propitiation for our sins and therefore makes it possible for us to be saved, 1 John 4:10. This is how God loved the world, by giving us a Savior Who was able to satisfy the righteousness of God and provide a sacrifice for the sending away of sin.
Under the Old Testament, The Mosaic Law, God had them build an Ark for the Covenant to reside within and as a place of propitiation for the sins of the people, Exodus 25:10. Often translated as mercy seat, the place between the Cherubim on the Ark was a place of atonement or propitiation, a place of covering (כַּפֹּ֫רֶת kapporet), not of mercy, Exodus 25:17. Either kindness (חֶסֶד kesed), Psalm 23:6, compassions (רַחֲמִים rahamim), Genesis 43:14, or favor (חנן kenen), Job 9:15, are translated as mercy in many English translations; however, they do not all carry a meaning of relief from sin. Paul quotes Jeremiah 31:34 in Hebrews 8:12. For I will be a satisfaction (ἵλεως) to their unrighteousness and their sins I will never remember. Pardon (סלח seleh), found in Jeremiah, is translated by using satisfaction (ἵλεως), not mercy (ελεος). Romans 9:15 shows us that mercy in the Old Testament is expressed by favor (חנן kenen). Therefore, propitiation is not the same as mercy. Rather, propitiation relates to atonement, which is the covering of sin.
Christ’s propitiatory work on the cross provided a satisfaction for the righteousness of the Father concerning the sins of Satan, the angels that followed him, along with humans, showing that He was just in deferring punishment on previously committed sins. However, punishment is still coming for those who reject God, for Christ’s work on the cross did not satisfy the wrath of God. Satan, his angels, and all humans who reject God will face punishment for their works, but not for their sins, because Christ made a satisfaction for them. However, propitiation is not equivalent to salvation. Propitiation shows that God is righteous in providing salvation by faith through grace based on Christ’s death for sins, according to the Scriptures, and His resurrection on the third day, according to the Scriptures, thereby, sending away the trespasses and sins of those who believe, Colossians 1:14 (sins); Ephesians 1:7 (trespasses).