Ever wonder what lies behind the meaning of words like “redemption”, “reconciliation” and “propitiation”? Curious about how the Passover, Day of Atonement, and the Mosaic sacrificial system all relate to Jesus’ work on the cross? If these are questions you are asking then I recommend The Atonement.
I will share one of the things that stuck with me as I read through it for class.
On the idea of reconciliation Morris reminds us of an important truth.
[Reconciliation] implies three states: first friendship, then a quarrel, then friendship again. [p 133]
The use of the word reconciliation reminds us that we started off as friends of God. In the world we live in with all the pain and brokenness, it can be easy to forget that fact. Friendship did exist until its bonds were broken. This “quarrel” finds its start in the Fall (Gen 3) and carries on in the sin of all mankind (Rom 3:10-18,23). Like any broken relationship there is now a problem that needs to be dealt with so that the parties involved can enjoy a renewed relationship.
There is no ignoring reality. A barrier remains a barrier until it is taken away. At the heart of the idea of reconciliation there is the thought that getting people together means dealing effectively with whatever it was that was keeping them apart. This way of looking at the cross then reminds us that there can be no fellowship between God and men unless and until the barrier of sin has been taken out of the way. [p 146]
But we don’t usually see it this way. At a time when “live and let live” is the motto of the age, tolerance means acceptance of everything, and problems are solved by kicking them down the road it is easy to see why people wonder – what is the big deal? Why does God really care about my issues, if nobody else does? I thought God was supposed to be loving, so why do we need Jesus?
Morris pours water on these ideas:
[the barrier] will not go away by wishing. We often seem to act on the assumption that, if we sit quietly and wait, any unpleasant thing will go away. It will not. It does not happen in the ordinary affairs of everyday life and it does not happen in the matter of the sin that separates us from God. Modern man finds this difficult to accept. 
Why is this difficult to accept:
Sinful man is always ready to let bygones be bygones. He is not greatly concerned by those small sins he perceives in himself and he cannot imagine why God should be. He is quite ready to let the past remain in the past and simply be friends with God in the present. There is nothing from his side that demands there be enmity. 
Man from his side of the relationship might downplay the barrier, but that is because he is responsible for creating it. No matter how we feel about our sin and God, we have to remember it is God that has been wronged, not us.Since God is the wronged party it is up to Him to determine if and how the barrier to the relationship will be dealt with.
God’s character, particularly holiness, would not allow the issue to be ‘swept under the carpet’. However, His character of love would not let the barrier remain in the way of the relationship either. No, God loved us enough to deal with the issue directly and in a way that was permanent. And that was only done through the cross.
[For the NT preachers], Christ’s death on the cross was the central thing. That death dealt effectively with sin so that it no longer features as an obstacle. 
With the barrier removed there are no obstacles left to a restored relationship (2 Cor 5:18-19).
God reconciled us to himself through Christ, … not counting people’s trespasses against them …
But when only one party acts we still don’t have a restored relationship. That will not happen until both parties work through the problem. We must still do our part to ‘be reconciled to God’ (2 Cor 5:20). And that is to approach God through faith in Jesus.