2 Corinthians 5:21

"God made [Jesus], who knew no sin, to become sin for us, so that, in Him, we might become the Righteousness of God."

Powerful words that rightly sum up practically the entire New Testament, and certainly the Gospel.

I've been reading John Stott's Magnum Opus: the Cross of Christ in my Bible study and have just finished a chapter on four different ways to view the effects of salvation.
1) Propitiation, from the Temple Mount.  God, through Jesus, satisfied His own wrath by fully and completely bearing it on behalf of sinful humanity.  In doing so, Jesus both fully absorbed God's wrath and fully bore our sins away from us, accomplishing the jobs of both the sacrificial Lamb and the Scapegoat on the Day of Atonement (Lev. 16)

2) Redemption, from the slave markets.  God paid the price on our heads (life-blood) to Himself to satisfy His own code of law.

3) Justification, from the court room.  God pronounced us completely justified and "brought forward into the present the verdict that belonged to the last judgement...by sending His own Son in the likeness of our sinful nature to be a sin offering, God actually condemned our sin in the human Jesus.  It is only because He was condemned that we could be justified" (Stott, 189)

4) Reconciliation, from the family room.  God initiated the reconciliation of believing sinners to Himself by 1) removing His wrath from us and 2) removing our sin from His sight.  By destroying the grounds for enmity, God creates reconciliation.  And we, who were once far off from God and cut off from the covenant people are now brought near and bound to both God and His Church through Jesus.

Stott ends with the passage above and a quote from Martin Luther: "Lord Jesus, you are my righteousness, I am your sin.  You took on you what was mine; yet set on me what was yours.  You became what you are not, that I might become what I am not."