This means the turning away of wrath by an offering. It is similar to expiation but expiation does not carry the nuances involving wrath. For the Christian the propitiation was the shed blood of Jesus on the cross. It turned away the wrath of God so that He could pass “over the sins previously committed,” (Rom. 3:25). It was the Father who sent the Son to be the propitiation (1 John 4:10) for all (1 John 2:2).
From Latin “propitiare” to appease, from propitius, meaning gracious.
Propitiation is translated from the Greek hilasterion, meaning “that which expiates or propitiates” or “the gift which procures propitiation”. The word is also used in the New Testament for the place of propitiation, the “mercy seat”. Hebrews 9:5. There is frequent similar use of hilasterion in the Septuagint, Exodus 25:18 ff. The mercy seat was sprinkled with atoning blood on the Day of Atonement (Leviticus 16:14), representing that the righteous sentence of the Law had been executed, changing a judgment seat into a mercy seat (Hebrews 9:11-15; compare with “throne of grace” in Hebrews :14-16; place of communion, Exodus 25:21-22).
Another Greek word, hilasmos, is used for Christ as our propitiation. 1 John 2:2; 4:10, and for “atonement” in the Septuagint (Leviticus 25:9). The thought in the Old Testament sacrifices and in the New Testament fulfillment, is that Christ completely satisfied the just demands of a holy God for judgment on sin, by His death on the Cross of Calvary.