Thank you brothers for your encouraging words and especially for the reference to the concordance, which I have added to my favorites. A few thoughts from my study.
I started by looking at the at references to atonement in the law. The Levitical references to atonement are mainly to do with the priest making atonement through shedding of blood for the sins and trespasses of the people. Jesus certainly came to do this. He was for God the sacrificial lamb, promised to Abraham in place of Isaac his son. In this way, he, who was sinless, took all our sins in his own body on the tree and became a propitiatory sacrifice for the sins of the whole world.
This propitiation is shown by Peter
"Who his own self bare our sins in his own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed" 1 Peter 2:24
"For all have sinned, and come short of the glory of God; Being justified freely by his grace through the redemption that is in Christ Jesus: Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;" Rom 3. 23 - 25
"And if any man sin, we have an advocate with the Father, Jesus Christ the righteous: And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world." 1 John 2:1-2
Without Christ's sacrifice and atonement, we would still be in our sins, But God looks on his son and is entirely satisfied with his finished work.
But this work alone would not deal with our nature which is sin in our flesh. Paul, in 2 Cor.5 speaks not of atonement or propitiation, but of reconciliation.
"Wherefore henceforth know we no man after the flesh: yea, though we have known Christ after the flesh, yet now henceforth know we him no more. Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new. And all things are of God, who hath reconciled us to himself by Jesus Christ, and hath given to us the ministry of reconciliation; To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation. Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ's stead, be ye reconciled to God. For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him." 2 Cor 5:16-21 (KJV)
On the cross, having born our sins and taken the just punishment for them in his own body, the holy spirit reveals through Paul that "he was made sin". I pause for a long time when I read this as it is beyond my understanding how he could voluntarily become sin. But because of his great love, he paid the wages of sin for us, and rose up triumphing over sin and death, "that we might be made the righteousness of God in him." Not just be made righteous through atonement, but be made the righteousness of god "Even the righteousness of God which is by faith of Jesus Christ unto all and upon all them that believe" Rom 3.22
We have a full and complete gospel to preach, atonement, yes, and more than atonement. Reconciliation to God