For Christians, knowing what God did in the cross of Christ is vital for understanding our faith. Moreover, if we intend to share the gospel, make disciples, or defend the faith, we need to understand these truths as well, starting with the necessity and the nature of the cross. Therefore, learning why and what the cross achieved is foundational for the faith.
In 1955 John Murray released his classic work on the cross and salvation, Redemption Accomplished and Applied. This week, the men in our church are discussing this book. And in preparation, I re-read the opening chapters on the necessity and the nature of the cross.
For those who have asked questions about why the cross was needful and what the cross accomplished, Murray is a great start—even if you might need to keep Dictionary.com close at hand. In his book, he gives a solid defense of the faith and he offers cogent from a Reformed perspective. Over the years, I have often assigned this book for class and returned to it myself.
In what follows I offer sixteen quotations from the book organized around seven truths related to the necessity and nature of the cross. Indeed, if you want to know what the cross achieved, Murray’s book is a great introduction. And hopefully what follows will give you a helpful introduction to Murray.
(N.B. The page numbers that follow are based on the 1955 Eerdmans copy, the one without Carl Trueman’s forward. Additionally, if you are interested you can find the e-book on Hoopla.)
Seven Truths about the Cross
- The Necessity of the Cross
John Murray begins his book with a chapter on the necessity of the cross, where he identifies two kinds of necessity—hypothetical necessity and consequent absolute necessity (11). Murray recognizes the former as something held by those like Augustine and Aquinas, while arguing for the latter. Regarding, “consequent absolute necessity,” he writes,
 The word “consequent” in this designation points to the fact that God’s will or decree to save any is of free and sovereign grace. To save lost men was not of absolute necessity but of the sovereign good pleasure of God. The terms “absolute necessity,” however, indicate that God, having elected some to everlasting life out of his mere good pleasure, was under the necessity of accomplishing this purpose through the sacrifice of his own Son, a necessity arising from the perfections of his own nature. In a word, while it was not inherently necessary for God to save, yet, since salvation had been purposed, it was necessary to secure this salvation through a satisfaction that could be rendered only through substitutionary sacrifice and blood-bought redemption. (11)
This point is important because it matches the justice of God with his mercy. God would not be unrighteous to put sinners to death, for the wages of sin is death, but he would be unrighteous to save sinners without the cross of Christ. Hence, the cross is necessary. Yet, instead of simply drawing a logical deduction about the cross, he turns to prove his point from Scripture, and he concludes in this way,
 For these reasons we are constrained to conclude that the kind of necessity which the Scriptural considerations support is that which may be described as absolute or indispensable. The proponents of hypothetical necessity do not reckon sufficiently with the exigencies involved in salvation from sin unto eternal life; they do not take proper account of the Godward aspects of Christ’s accomplishment. If we keep in view the gravity of sin and the exigencies arising from the holiness of God which must be met in salvation from it, then the doctrine of indispensable necessity makes Calvary intelligible to us and enhances the incomprehensible marvel of both Calvary itself and the sovereign purpose of love which Calvary fulfilled. The more we emphasize the inflexible demands of justice and holiness the more marvelous become the love of God and its provisions. (18)
- Passive and Active Obedience
When discussing the nature of the cross, Murray makes obedience the theological umbrella under which every aspect of the cross (e.g., sacrifice, propitiation, reconciliation, redemption, etc.) is considered (19ff). Fine-tuning his point, he appeals to the historic distinction between active and passive obedience. Clarifying these terms, he writes,
 The distinction between the active and passive obedience is not a distinction of periods. It is our Lord’s whole work of obedience in every phase and period that is described as active and passive, and we must avoid the mistake of thinking that the active obedience applies to the obedience of his life and the passive to the obedience of his final sufferings and death. The real use and purpose of the formula [passive and active obedience] is to emphasize the two distinct aspects of our Lord’s vicarious obedience. The truth expressed rests upon the recognition that the law of God has both penal sanctions and positive demands. (21)
- The Personal Obedience of Christ
Next, Murray stresses the personal nature of Christ’s obedience. In other words, it is not simply Christ’s act of dying that saves sinners, it is also his inner disposition and obedience.
 When we speak of obedience we are thinking not merely of formal acts of accomplishment but also of the disposition, will, determination, and volition which lie back of and are registered in these formal acts. And when we speak of the death of our Lord upon the cross as the supreme act of his obedience we are thinking not merely of the overt act of dying upon the tree but also of the disposition, will, and determinate volition which lay back of the overt act. (22)
- The Cross as Sacrifice
After tackling the overarching theme of Christ’s obedience, Murray moves on to cover four biblical metaphors for the cross. The first is sacrifice. Starting with the sacrificial system in Israel, he writes,
 The Old Testament sacrifices were basically expiatory. This means that they had reference to sin and guilt. Sin involves a certain liability, a liability arising from the holiness of God, on the one hand, and the gravity of sin as the contradiction of that holiness, on the other. The sacrifice was the divinely instituted provision whereby the sin might be covered and the liability to divine wrath and curse removed. The Old Testament worshiper when he brought his oblation to the altar substituted an animal victim in his place. (25)
Acknowledging the great distance between an animal and a man, Murray explains how these “shadows and patterns” prepared the way for Christ. And in Christ, we have the fulfillment of the sacrificial system.
 Jesus, therefore, offered himself a sacrifice and that most particularly under the form or pattern supplied by the sin-offering of the Levitical economy. In thus offering himself he expiated guilt and purged away sin so that we may draw near to God in full assurance of faith and enter into the holiest by the blood of Jesus, having our hearts sprinkled from an evil conscience and our bodies washed with pure water. (26–27)
While I would take issue with Murray’s reduction of Christ’s sacrifice to that of the sin offering, he is correct to say that Christ died to purge away sin. Moreover, he is right to affirm our need to look to the Levitical patterns of sacrifice to understand the cross. As he notes, “We must interpret the sacrifice of Christ in terms of the Levitical patterns because they were themselves patterned after Christ’s offering” (27). Without them, we cannot make sense of the meaning of Christ’s cross. But with them, we are given a multi-faceted object lesson explaining the logic of sacrifice, as well as confidence that what God began typologically has been completed Christologically. That is to say,
 If the Levitical sacrifices were expiatory, how much more must the archetypal offering have been expiatory, and expiatory, be it remembered, not on the plane of the temporary, provisional, preparatory, and partial but on the plane of the eternal, the permanently real, the final, and the complete. (27)
In asking what did the cross achieve? Or what is the essence of the cross? We must begin with sacrifice. And not just the word, but the whole system of sacrifice outlined in the Law of Moses. At the heart of this logic is God’s provision for wiping away sin. This is called expiation, and it promises that the blood of a perfect sacrifice can wipe clean our guilt by covering our sin.
- The Cross as Propitiation
If the cross expiates our sin, it also propitiates the wrath of God. While these words have been confused and often juxtaposed to one another, they are actually two independent-but-related ideas that both have a place in Christ’s cross. Christ’s death deals with sin (expiation) and by means of expiation, the wrath of God is propitiated. Taking these ideas together, Murray is right to define propitiation in personal terms.