I ask: What was achieved on the cross?
PROPITIATION: Appeasement of an offended party from wrath or anger.
REDEMPTION: What is required in order to liberate from oppression, enslavement, or another type of binding obligation.
JUSTIFICATION: Divine, forensic act of God, based on the work of Christ upon the cross, whereby a sinner is pronounced righteous by the imputation of the righteousness of Christ.
RECONCILIATION: Bringing together of two parties that are estranged or in dispute.
Where is the proof?
Love consists in this: not that we loved God but that He loved us and sent His Son to be the propitiation for our sins.
1 John 4:10 (HCSB)
For you know that you were redeemed from your empty way of life inherited from the fathers, not with perishable things like silver or gold, but with the precious blood of Christ, like that of a lamb without defect or blemish. 1 Peter 1:18-19
For in it God’s righteousness is revealed from faith to faith, just as it is written; the righteous will live by faith. Romans 1:17
Since we have now been justified by his blood, how much more shall we be saved from God’s wrath through him! For if, while we were God’s enemies, we were reconciled to him through the death of his Son, how much more, having been reconciled shall we be saved through his life! Not only is this so, but we also boast in God through our Lord Jesus Christ, through whom we have now received reconciliation.
Romans 5:9-1
All definitions from the Holman Illustrated Bible Dictionary
Scripture quoted from the New International Version