The one doctrine in Romans 3:21-26 that most expresses penal substitution is the doctrine of propitiation. Grudem’s definition makes this point: “Propitiation is a sacrifice that bears the wrath of God against sin and thereby turns God’s wrath into favor.”[1]
Propitiation is the result of the penal substitutionary death of Christ experiencing God’s wrath. This exact word for propitiation (ἱλαστήριον [hilasterion]) in Romans 3:25 is found only one other time in Hebrews 9:5 about the “mercy seat” in the Holy of Holies.
D. A. Carson noted the importance of this word for propitiation: “The one other NT occurrence of the word (Heb 9:5) certainly refers to the mercy seat, and so do twenty-one of the twenty-seven occurrences in the LXX. It follows, then that Paul is presenting Jesus as the ultimate ‘mercy seat,’ the ultimate place of atonement, and derivatively, the ultimate sacrifice.”[2]
Propitiation is appropriated by faith in Christ based on Christ’s shed “blood” in Romans 3:25.
Propitiation “shows” that God “with forbearance passed over” judging the “former” Old Testament sins on the Day of Atonement until Jesus paid the price on the cross. There God judged His Son for the sins of Old Testament sinners and the sins of all sinners. The doctrine of penal substitution demands that Christ bore the punishment of our sins.
Propitiation “shows” in 3:26 “for the present time his righteousness that He might be just and the justifier of him who believes in Jesus.” Here “righteousness” refers to God’s attribute of righteousness i.e., His justice. Sin must be paid for, or God would be unjust. Not only was the love of God demonstrated at the cross but the justice of God. Both His love and His justice met at the cross. John combined the doctrine of propitiation and the attribute of God’s love in 1 John 4:10. Michael Horton elaborated on this combination in his discussion of propitiation:
As long as there is the reality of divine wrath, the reality of divine propitiation will be warmly received as its antidote. It is God’s love that moves him to provide his own satisfaction of justice. Rather than being set in opposition, God’s love and the propitiatory sacrifice of his Son are mentioned in the same breath, for example, in Romans 3:25 and 1 John 4:10.[3]
Propitiation is also mentioned in 1 John 2:2 and 4:10. The Greek word hilasmos [ἱλασμός] used in the New Testament is found only in 1 John 2:2 and 4:10. Colin Kruse argued that the LXX used the Greek word hilasmos and supports the idea of propitiation as a satisfying of God’s wrath: “It occurs six times in the LXX (Lev 25:9; Num 5:8; Ps 129:4 [= 130:4 ET]; Ezek 44:27; Amos 8:14), and in every case except Amos 8:14 it relates to the removal of guilt because of sin, which in most places (Ps 129:4 and Amos 8:14 are the only exceptions) is effected through sacrifice.[4] Kruse also contended that the context of 1 John 2 supports the idea of propitiation:
Clues as to what the author meant by saying that Jesus Christ is ‘the atoning sacrifice for our sins’ in 2:2 will have to be sought within the immediate context. And the idea of the atoning sacrifice here is in juxtaposition with the idea of advocacy. Jesus is the one who speaks to the Father in our defense when we sin. This suggests that he is, as it were, pleading for mercy for sinners, and this in turn suggests that his role as the atoning sacrifice is to secure that mercy; that is, he is, in this context, the propitiation for our sins.[5]
In justification, the sinner is declared righteous but in propitiation, God is declared righteous because God the righteous judge of the universe has punished sin in His Son’s penal substitutionary death. He punished all sinners’ sins in His son on the cross. Paul teaches the necessity of God’s punishment of sin in His Son. Because of propitiation, God can be just when He declares the believing sinner righteous because the sinner’s sins were punished in his Son. If Christ offered Himself as the satisfaction of God’s wrath against sinners, then any sinner “who believes in Jesus” can be justified (Romans 3:26).
These doctrines are inexorably related to the doctrine of penal substitution: the wrath of God, imputation, prophets, faith, sin, the deity of Christ, justification, imputation, redemption, and propitiation.
[1] Wayne Grudem, Systematic Theology, 575.
[2] D. A. Carson, “Atonement in Romans 3:21-26” in The Glory of The Atonement, 129. R. Laird Harris wrote that kapporet [כַּפֹּ֫רֶת] meant mercy seat (Exodus 25:17) and “this noun is used twenty-seven times and always refers to the golden cover of the sacred chest in the inner shrine of the tabernacle or temple ... the translation ‘mercy seat’ does not sufficiently express the fact that the lid of the ark was the place where the blood was sprinkled on the day of atonement. ‘Place of atonement’ would perhaps be more expressive.” (R. Laird Harris, Theological Wordbook of the Old Testament, vol. 1 [Chicago: Moody Press, 1980], 452). Again, the satisfaction of God’s wrath is inherent in these texts. The reason God’s mercy is needed is that God judges sin unless His justice and wrath are propitiated.
[3] Michael Horton, The Christian Faith (Grand Rapids: Zondervan, 2011), 500.
[4] C. G. Kruse, The Letters of John (Grand Rapids, MI; Leicester, England: W.B. Eerdmans Pub.; Apollos. 2000), 73.
[5] Ibid., 74.