This is a great post from Justin Taylor:
Redemption from sin cannot be adequately conceived or formulated except as it comprehends the victory which Christ secured once for all over him who is the god of this world, the prince of the power of the air . . .
[I]t is impossible to speak in terms of redemption from the power of sin except as there comes within the range of this redemptive accomplishment the destruction of the power of darkness.
(Redemption—Accomplished and Applied, p. 50)
Colossians 2:14-15 is a key verse in this regard.
Paul lists two results of Christ’s work on the cross: (1) Christ disarmed the rulers and authorities, and (2) he publicly shamed them.
How? By triumphing over them in himself.
So how does Christ bearing God’s wrath for sinners, taking their sin as a substitute, constitute a victory over Satan?
George Smeaton (1814–1889), Professor of Exegetical Theology at New College, Edinburgh, provides the answer.
Sin was (1) the ground of Satan’s dominion, (2) the sphere of his power, and (3) the secret of his strength; and no sooner was the guilt lying on us extinguished, than his throne was undermined, as Jesus Himself said (John 12:31). When the guilt of sin was abolished, Satan’s dominion over God’s people was ended; for the ground of his authority was the law which had been violated, and the guilt which had been incurred. . . .
[A]ll the mistakes have arisen from not perceiving with sufficient clearness how the triumph could be celebrated on His cross. (The Apostles’ Doctrine of the Atonement (Edinburgh, T. & T. Clark, 1870), 307–308; my emphasis and numbering)
In other words, Satan’s power is based on sin and guilt; Christ’s death meant the ultimate death of sin, guilt, and death itself; and thus Satan was ultimately defanged by Christ’s atoning work.
As Smeaton says, “it was on God’s part at once a victory and a display of all God’s attributes, to the irretrievable ruin, dismay, and confusion of satanic powers.”
So it’s not Christus Victor (Christ defeating his enemies) instead of propitiation (Christ bearing God’s wrath)–rather, it’s Christus Victor because of propitiation. Both are gloriously important, but only in that order.