Propitiation. Most people are not familiar with this word; however it is the most important word in your life. This is because propitiation describes the act of the removal of God’s wrath from those who have faith in Christ.
As can be seen above in Romans 3:23, every person who has ever existed, or will exist, is a sinner. If you think you are a good person, you are deceived. You are not good; you are rebellious against your Creator. Justice demands that this act of rebellion be punished. This punishment is God’s wrath. Because God is infinitely holy, the punishment must match the crime, therefore, God’s punishment for our rebellion is eternal torment, i.e. hell.
However, God, because he is rich in mercy and grace, “put[s] forward” Christ Jesus. This is the idea of presenting, or to set forth before the public. The Christ (the prophesied Messiah of the Old Testament) is put forward to remove the wrath of God that looms above all man. This putting forward of Jesus appeases (or propitiates) the wrath of God. It satisfies God’s demand for justice to be served. This is why is says in verse 26 above, “so that he might be just and the justifier.” God plays both sides, so that he gets all the glory. His justice and his love are on full display by putting forth his only Son.
The way that the Messiah, the Christ, does this is by “his blood.” This is an obvious reference to the death of Christ upon the cross. It was on the cross that God poured out his wrath upon Jesus for the sins of the elect. (“I am the good shepherd. The good shepherd lays down his life for the sheep.” - John 10:11 and “Husbands, love your wives, as Christ loved the church and gave himself up for her” – Ephesians 5:25).
The way the propitiation of the blood of Jesus is applied is through faith, not faith plus the sacraments, faith alone. Through faith by Grace we are justified before God through the blood of Christ Jesus. Nothing more and nothing less. Faith alone. Grace alone. Christ alone.
This is the heart of the Gospel; our atonement through the sufficient sacrifice of Christ Jesus. And this is why we sing verses such as “What can wash away my sins? Nothing but the blood of Jesus.” At the end of the day, God gets all the glory, and we get all of the good.