Rich, rich, rich, is what the word propitiation is. The Greek hilasterios is used to speak of the mercy seat; that place where the wrath of God was propitiated, satisfied and appeased by means of an acceptable sacrifice. In the Old Testament tabernacle, the mercy seat was the lid of the Ark of the Covenant (Exod 25:20) It was called the mercy seat because it was here the High Priest satisfied God’s demand for a sacrifice for sin by the sprinkling of blood on the Day of Atonement and thus, the nation received God’s mercy. To show His acceptance of the sacrifice offered in the obedience of faith God rested upon the mercy seat in the form of a cloud.
When we come to the New Testament, then, the mercy seat is the Lord Jesus Christ. He is the one “whom God displayed publicly as a propitiation in His blood through faith” (Rom 3:25). In looking forward toward the cross, God “passed over the sins previously committed,” knowing that His wrath against sin would be ultimately satisfied and His righteousness displayed by the perfect sacrifice of His perfect Son. This was the purpose of the incarnation: “Therefore, He had to be made like His brethren in all things, that He might become a merciful and faithful high priest in things pertaining to God, to make propitiation for the sins of the people” (Heb 2:17). In the death of Christ, God’s wrath has been appeased, His righteousness displayed as both the Just and the Justifier, and the door to God thrown wide open. The empty tomb is proof!
None of this would have been possible had the eternal Word not become flesh and dwelt among us (Jn 1:14).