2 Corinthians 5:21
For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God.
I have been reading 2 Corinthians in my devotions and sometimes verses like this just smack me across the face.
Take a look at what the ESV Study Bible note has to say on this verse: (remember this is all off of one verse)
5:21 This verse is one of the most important in all of Scripture for understanding the meaning of atonement and justification.
Here we see the one who knew no sin is Jesus Christ (v.20) and that he (God) made him(Christ) to be sin (Gk. harmartia, “sin”). This means that God the Father made Christ to be regarded and treated as “sin” even though Christ himself never sinned (Heb. 4:15; cf. Gal. 3:13). Further we see that God did this for our sake– that is, God regarded and treated “our” sin (the sin of all who would believe in Christ) as if our sin belonged not to us but to Christ himself. Thus Christ “died for all” (2 Cor. 5:14) and, as Peter wrote, “He himself bore our sins in his body on the tree” (I Pet. 2:24). In becoming sin “for our sake,” Christ became our substitute, thereby bore the wrath of God (the punishment that we deserve in our place (“for our sake”). Thus the technical term for this foundational doctrine of the Christian faith is the substitutionary atonement– that Christ has provided the atoning sacrifice as “our substitute, for the sins of all who believe (cf. Rom. 3:23-25).
The background for this is Isaiah 53 from the Greek (Septuagint) translation of the Hebrew OT, which includes the most lengthy and detailed OT prophecy of Christ’s death and which contains numerous parallels to 2 Cor. 5:21. Isaiah’s prophecy specifically uses the Greek word for “sin” (Gk. hamartia) five times (as indicated below in bold font)
“surely he has born our GRIEFS; He was crushed by our INIQUITIES; the Lord has laid on him the INIQUITY of us all; he shall bear their INIQUITIES; he bore the SIN of many” (Isa. 53:5-12)
In a precise fulfillment of this prophecy, Christ became “sin” for those who believe in him, so that in him we might become the righteousness of God.