The Atonement is not just about the cross

Unfortunately, some theories of the Atonement focus almost exclusively on the cross. These theories see the Atonement as being about Jesus dying on our behalf to provide complete satisfaction for the dishonor done to God the Father by our sin.

Viewed from this perspective, the Atonement is about justice, and it principal gift is forgiveness

However, such theories fall far short of the biblical revelation. Note the Apostle Paul's words: 

If Christ has not been raised, your faith is futile and you are still in your sins. (1Cor 15:17) 

Commenting on this verse in The Soul of Ministry, Ray Anderson says this: 
It is the resurrection of Jesus, not just his death on the cross, that completed the Atonement... It is not just sin that needs to be forgiven, but death that needs to be overcome.... The great human dilemma is death, not merely sin" (p98). 
Viewed from the perspective of the full testimony of Scripture, the Atonement is about restoring human fellowship with God and its principal gift is new life in Christ.

According to Alan Torrance, this new life is about "sharing through the Spirit in the incarnate Son's communion with the Father." Anderson elaborates on this Trinitarian, incarnational understanding of the Atonement:
If Jesus assumed a human nature subject to death in his conception and birth, then death was inevitable for him, regardless of the means. Yes, there was in retrospect, after the crucifixion of Jesus, ample evidence in Scripture that even the means of death had been foreseen by God. But death on a cross [per se] was not necessary, only that the death assumed by Jesus be completed and that he be raised from the dead in order for the Atonement to be completed and humanity restored to fellowship with God (p98).
As Anderson notes, Paul's language about the Atonement is deeply rooted in metaphors that speak not only of death, but also of resurrection (and ascension):
You were dead through the trespasses and sins....But God, who is rich in mercy, out of the great love with which he loved us even when we were dead through our trespasses, made us alive together with Christ--by grace you have been saved--and raised us up with him and seated us with him in the heavenly places in Christ Jesus (Eph 2:1, 4-6, NRSV).
Note how Paul mentions the human condition (death), from which we are liberated by being made alive (resurrected) with Christ, then exalted (ascended) with Christ.

The point is this: the Atonement is not merely about dealing with the sin problem. Certainly, sin is a problem for humanity, and Jesus' incarnation, life, death, resurrection and ascension deals decisively with it. However, if the Atonement is only about forgiving sin, then its result would be a dead (though forgiven!) corpse.

Thankfully, the Atonement goes beyond achieving forgiveness, all the way to granting us fullness of life - our sharing through the Holy Spirit in the life that the incarnate Son of God (Jesus) has with the Father

And Jesus accomplished atonement for us with God not simply by dying so that we could be forgiven our sin debt, but by assuming (taking into himself) what is dead (our diseased-fallen humanity) and in union with us going all the way to death and then beyond that death for us and with us to resurrection - taking our humanity to a new birth (the re-birth or re-creation of our humanity, in Christ). Then continuing to be human, and thus still in union with us, Jesus ascended and in him our humanity is glorified.

It is thus inaccurate (or, at at least, incomplete) to say that "the work of Christ on the cross saves us" (implying that his work was limited to his sacrificial death). As Anderson notes, "the cross must be viewed backward through the resurrection" (p99), for in the resurrection we see that Jesus' death destroyed human death (the curse of sin), and thus no longer has the power to determine our human destiny. Our human destiny is now not in Adam, but in the new Adam, Jesus Christ - the incarnate Son of God now risen and ascended.

As we celebrate Holy Week this year, let us rejoice in the fullness of who Jesus is and what he has done for our salvation/atonement. Let us look back to Christmas (which celebrates Jesus' birth and thus points to the Incarnation) and be reminded that the one who was crucified on Good Friday and raised from the dead on Easter Sunday is none other than the Son of God become (and remaining) human with us and for us. Jesus, in every respect, is and forever remains our representative and substitute (God incarnate for us).

Let us remember Jesus, standing in for us, took upon himself our sinful/diseased humanity, and through his vicarious life, broke the power of sin and death for us - healing our brokenness and granting us entrance into true life, which is our sharing in his intimate communion with the Father through the power of the Holy Spirit.