What Is Penal Substitution?
According to the apostle Paul, the death and resurrection of Jesus are the “first things” of the gospel (1 Cor 15:3–4).  Christians have debated both of these first things throughout the history of the church. Regarding Jesus’ death, they have debated whether the New Testament teaches penal substitution and (if so) whether penal substitution should be understood as the central atonement model in the New Testament. 
Recent work on substitution has simply argued for the presence of substitution in the New Testament with specific reference to selected texts in Paul’s letters.  In this article, I argue that the New Testament teaches Jesus’ death was a penal substitute for sinners. Elsewhere I defined penal substitution in the following way:
Jesus died a violent, substitutionary death to be a sacrifice of atonement for the sins of Jews and Gentiles. By this death, Jesus took upon himself God’s righteous judgment and wrath against the sins of those for whom he died. By dying as their penal substitute, Jesus paid the penalty for their sins, and he therefore both propitiated God’s wrath against their sins and expiated their sins so that the sins of Jews and Gentiles would be forgiven and so that they would be justified by faith, forgiven of their sins, reconciled to God, reconciled to each other, participate in the future resurrection, and saved from God’s wrath. 
I support the above thesis and definition by analyzing Romans 5:6–10. I make one primary argument from the preceding text to support my thesis. Namely, Jesus died for sinners to justify them by faith, to reconcile them to God, and to save them from God’s eschatological wrath.
THE IMMEDIATE CONTEXT OF ROMANS 5:6–10
Paul’s remarks about Jesus’ death in Romans 5:6–10 occur in the context of providing a reason why Christians have hope in suffering. In Romans 5:1–5, Paul says Christians have hope in suffering “because we have been justified by faith,” and consequently “we have peace with God through our Lord Jesus Christ through whom we have access by faith into this grace in which we stand” (5:1–2). The theological truth of our right standing before God because of justification by faith in Christ leads Paul to say Christians can “boast” in God when they suffer (v. 3), because suffering produces perseverance (v. 3), perseverance produces tested and proven character (v. 4), and tested and proven character produce hope (v. 5).
Paul quickly declares that hope will not put the hopeful to shame in the judgment (v. 5), because all who have love for God through Christ likewise have the Holy Spirit living in their hearts (v. 5). Then, in verses 6 to 10, Paul gives the undergirding reason why those who have been justified by faith have hope and have the Spirit living in their hearts: Christ died for their sins to give them specific saving benefits.
JESUS’ DEATH FOR SINNERS AND ITS SAVINGS BENEFITS
In Romans 5:6, Paul asserts Jesus died for the weak in the appropriate time while they were “still weak.” The “weak” in verse 6 refers to the “ungodly” in verse 6 and to the “sinners” in verse 8. Humans are conceived in sin because of Adam’s transgression (v. 12), and humans willingly participate in sinful actions (Rom 3:23). Contrary to the person who dies a noble or patriotic death for a righteous or good cause (5:7), Jesus died for “weak” and “ungodly” “sinners” (vv. 6, 8). His death for sinners achieves justification (v. 9), reconciliation (v. 10), and salvation (v. 9) for those for whom he died.
In Romans 5:9, Paul infers from his remarks in verse 8 that God’s love for sinners is chiefly seen by means of Jesus’ death for them while they were still in a state of sin. In verse 9, Paul says, “therefore,” future deliverance from God’s wrath is certain “because we have been justified by his blood.” Jesus’ penal substitutionary death is evident here not simply because Paul uses the phrase “for us” when he refers to Jesus’ death, but because Jesus’ sacrificial death “for us” justifies us in God’s law-court by faith and guarantees future deliverance from God’s wrath.
Christians have debated justification for centuries. The important point for my thesis is God declares “weak” and “ungodly” “sinners” not guilty. That is, he justifies them by faith because he does not reckon their transgressions against them (Rom. 4:6–8) since Jesus’ blood purchases the justification of all sinners who have faith in Christ (5:9; cf. 3:21–4:25). His death for them, which provides both forgiveness of sins (hence, the reference to blood) and justification (cf. also Rom 3:24–25; 5:9), also guarantees deliverance from God’s future wrath (i.e. salvation) (5:9), because Jesus died for sinners while they were sinners. In the words of 2 Corinthians 5:21: “God made him who knew no sin to become sin for us…” Or in the words of Romans 8:4: God made Jesus a sin-offering and condemned sin in Jesus’ flesh so that “the righteous requirement of the law would be fulfilled in us who are not walking according to the flesh but according to the Spirit.”
The concept of salvation (or soteriology) in Paul’s theology is complex. For the purpose of this article, I use the term salvation to refer to God’s future deliverance of his people from his eschatological wrath. Jesus purchased this deliverance by taking upon himself the penalty of those sinners for whom he died so that they would be declared not guilty in the day of judgment because God reckons to their account the perfect righteousness of Jesus Christ (Rom. 4:1–25). His death for sinners then in turn results in God’s deliverance of those for whom Jesus died from God’s final distribution of wrath at the end of history, a wrath that is stored up for all sinners who refuse to trust in Jesus by faith (cf. Rom 2:7–10).
Prior to Jesus’ wrath-bearing death for our sins, sinners hated God (Rom 5:10) and God hated them (Ps 5:5). This is why Paul says “we were enemies” prior to our becoming reconciled to God through the death of his son (Rom 5:10). But because Jesus died for our sins and took upon himself our wrath that we deserved, the “weak” and “ungodly” “sinners” and “enemies” of God now experience soteriological peace, which will result in exoneration in God’s law court and deliverance from God’s wrath on the last day (Rom 5:10). Because Jesus suffered God’s wrath for us, those who are justified by faith in Christ will receive the benefits of his saving death both now and in the age to come.
Jesus died for sinners to be their penal substitute. Future justification and salvation have already been realized now in the current age by faith in the lives of every Christian because Jesus died as our penal substitute and because God raised him from the dead (Rom 5:10; cf. 4:24–25). Evidence of the resurrection of Jesus from the dead is the life-giving and indwelling presence and power of the Spirit living in the hearts of and flowing freely by specific deeds of obedience in the lives of everyone who has been justified by faith (Rom 5:6; 8:1–11; cf. Gal 2:16; 3:13–14; 4:4–6; 5:16, 22). May every preacher far and near preach with absolute clarity the penal substitutionary nature of Jesus’ death for sinners scattered throughout the world.
 Unless otherwise indicated, translations of biblical texts are my own.
 For examples, see essays in James Beilby and Paul R. Eddy (eds.), The Nature of the Atonement: Four Views(Downers Grove, IL: InterVarsity Press, 2006); Steve Jeffery, Mike Ovey, and Andrew Sach, Pierced for Our Transgressions: Rediscovering the Glory of Penal Substitution (Downers Grove, IL: Inter-Varsity Press, 2007); J.I. Packer and Mark Dever, In My Place Condemned He Stood: Celebrating the Glory of the Atonement(Wheaton: Crossway, 2007).
 E.g. Simon J. Gathercole , Defending Substitution: An Essay on Atonement in Paul (Grand Rapids: Baker, 2015). Gathercole’s work is helpful since he engages some of the challenges to substitution in biblical scholarship and since he responds to each challenge with clear and accessible exegesis of selected texts. He also provides some practical application of the doctrine of substitution to the Christian life.
 With a few modifications, quote comes from Jarvis J. Williams, “Violent Atonement: The Foundation of Paul’s Soteriology in Romans.” Journal of the Evangelical Theological Society 53/3 (September 2010): 579-99.