That Christ died for our sins is beyond question. (1 Cor. 15:3; Rom. 5:8-11; 2 Cor. 5:21) In what sense was Jesus’s death for sin necessary, though? The issue of the necessity of atonement is a complex one involving many layers from various angles. John Murray sheds some light on at least one area by making a very helpful distinction in his work Redemption: Accomplish and Applied between two views of the necessity of Christ’s work on the Cross that have been held throughout the history of theology.
Hypothetical Necessity – First is the view that he terms “hypothetical necessity” (pg. 11), in which Jesus’ death is held to be not strictly necessary. Theoretically it is possible that God could have saved his church through some means other that Christ’s sin-bearing death, and victorious resurrection if he so chose. He is God for whom all things are possible. Apparently in his wisdom though, he found that this was the most fitting means in that it combines the greatest amount of blessings, virtues, and so forth. Murray cites Augustine and Aquinas as historical representatives of this view. Knowing what I know of them, it sounds like the sort of conclusion they might come to.
Consequent Absolute Necessity – The second view Murray calls “consequent absolute necessity” and it is apparently the historical Protestant position (Calvin, Institutes, II.16.5). It holds that, given God’s decision to save, Christ’s death for sin was absolutely necessary. So, to be clear, first, it affirms that strictly speaking, Christ’s death is unnecessary. God did not need Christ to die. He is perfect and complete in his own life before the creation or the redemption of the world without it. And yet, consequent, or logically-following his decision to save, it is absolutely necessary given the nature of sin and the nature of God that it should happen through Christ’s vicarious sacrifice. (pg. 12) So, if moved by love, God is going to save people in a way consistent with his own holy, just, and merciful character, the atonement is necessary. It is this view that Murray judges to be the correct one and to which I myself subscribe.
Support Some might find this to be ‘vain speculation’, but Murray points various texts to the effect that such a conclusion is warranted. (See pp. 13-18) One particular argument he forwards is connected to the fact that the Scriptures point to Christ’s death as greatest proof we have of the love of God (Rom. 5:8; 1 John 4:10) That God was willing to spare his own Son testifies to the costliness of his love. (Rom 8:32) Murray asks, “would the Cross be an extreme exhibition of love if there were no necessity for such costliness?” (pg. 17) Can’t we only draw that conclusion if there were no other options? If there wasn’t some extreme sense of necessity involved? I find that conclusion hard to escape. As another has pointed out, it makes no sense for your friend to tell you, “Look how much I love you!” and then jump into a lake and drown. If he jumps in front of a bus to push you out of the way, that’s another story.
Another theological objection is that this seems to put limits on God. Isn’t it arrogant to say what God can and can’t do? At one level yes, we ought to be careful about being too eager to say what God can’t or cannot do. That’s why Murray spends several pages showing that this is a judgment made on scriptural grounds; its safest to make judgments on what God has told us about himself. It must also be pointed out that there are several things it is perfectly fine to say God’s ‘cannot’ do which do not rob him of glory. God’s inability to lie, be wicked, or deny himself is no affront to his majesty. In fact, “such ‘cannots’ are his glory and for us to refrain from reckoning with such ‘impossibles’ would be to deny his glory and perfection.” (pg. 13)
So was Jesus’ death necessary? In one sense, no. Jesus didn’t need to die–he could have left us to our peril and woe. In another sense, once God decided (in some pre-temporal sense) to save us by grace, it could come in no other way than through the death of His Own Son.
Soli Deo Gloria