Contributors to Trevin Wax’s blog have recently been writing about some of the aspects of Christ’s atoning work:-

On the cross, Christ

• slays the dragon and wins our victory
• offers himself up as our substitute, drinking from the cup of God’s wrath
• redeems us from slavery to sin and death
• is the Lamb who takes away all our sin and shame
• sets us free to serve God with unfettered joy
• shows how God is with us in our suffering
• is the propitiation that puts us right with God
• provides our supreme example

No one image (let’s not call them theories, please!) of the atonement will suffice.  Christ’s cross-work is an inexhaustible mine, a multi-faceted diamond.