He himself bore our sins in his body on the tree, that we might die to sin and live to righteousness. By his wounds you have been healed. For you were straying like sheep, but have now returned to the Shepherd and Guardian of your souls. (RSV)
What did Jesus’ suffering accomplish? When Jesus died on the cross (the tree,) He fulfilled the requirement of the Law as a payment for sin. Deut 21:22-23 If a man guilty of a capital offense is put to death and his body is hung on a tree, you must not leave his body on the tree overnight. Be sure to bury him that same day, because anyone who is hung on a tree is under God's curse. You must not desecrate the land the Lord your God is giving you as an inheritance. (NIV) Jesus took the curse of God’s wrath upon sin on Himself. Over and over, it has been emphasized in the N.T. that Jesus was not guilty of any sin, yet He was executed. On the cross Jesus called out asking why the Father had forsaken Him indicating that God’s wrath was truly on Him. If Jesus were not guilty, then why would the Father abandon Him? The answer can only be that my sin was placed on Him. 2 Cor 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. (RSV)
How do I know that Jesus took my sin and that it was a satisfactory substitution for my death? I believe that the resurrection of Jesus proves that. Jesus made many statements about eternal life and that it only comes through Him. John 5:24 “Truly, truly, I say to you, he who hears my word and believes him who sent me, has eternal life; he does not come into judgment, but has passed from death to life.” 14:6 Jesus said to him, "I am the way, and the truth, and the life; no one comes to the Father, but by me." (RSV) Remember, if Jesus had committed only one sin, then His death would have been the payment only for His own sin. He would not be able to pay for mine. If either of these two statements that Jesus made are false, then He was a liar and could not possibly pay for my sin. Since God did raise Jesus from the dead, it proves that everything Jesus said is true. It proves that He and only He gives me eternal life so that I can go to the Father also.
If there were any other way for me to get eternal life, then Jesus’ death was a waste. Paul says in Gal 3:21b-22 For if a law had been given that could impart life, then righteousness would certainly have come by the law. But the Scripture declares that the whole world is a prisoner of sin, so that what was promised, being given through faith in Jesus Christ, might be given to those who believe. (NIV) He affirms, with Peter, that I am a sinner.
I went astray and now have come to Jesus, the Sheppard and Guardian of my soul. He who has saved me will guard me and keep me safe until that day He escorts me into the presence of the Father.
When Peter was writing these two short verses, He was either quoting from the O.T. or had it in mind. Read Isaiah 53: 4, 5, and 11. These verses are a vivid prediction of Jesus’ suffering and atonement for my sin.