JESUS PAID IT ALL
John 8:28 "Then said Jesus unto them, When ye have lifted up the Son of man, then shall ye know that I am he, and that I do nothing of myself; but as my Father hath taught me, I speak these things."
This is the second of three times that Jesus spoke of Himself being "lifted up" (1st - Jn. 3:14; 3rd - Jn. 12:32-33). As the scripture explains in John 12:33, this was a reference to crucifixion as the means of His death. The lifting up is speaking of being lifted up from the earth and suspended on a cross in crucifixion. The Jews understood that Jesus was speaking of death.
The crucifixion didn't just happen. It was planned by God. Does this mean that God bears all responsibility and those who were actually instrumental in the rejection and crucifixion of Jesus are not guilty? Not at all. Jesus came to the earth to die in our place and thereby purchase redemption for us. That was His plan but He didn't force anyone to fulfill it. His ministry and message placed Him in direct opposition with the devil and his followers. Their hatred for Jesus caused them of their own free will to crucify Jesus.
God, in all His wisdom, simply knew what man would do and He determined to use their rejection of His Son to accomplish His will. He never controls our will to accomplish His.
If a person truly understands the message of the cross, then he understands grace. Jesus didn't just make a token sacrifice for us. He paid it all. There's no sacrifice that we can make that will add to or replace the sacrifice of Christ. He did it all, and we can thank Him forever!