The crowd said to Jesus, "The Scriptures teach that the Messiah will live forever. How can you say that the Son of Man must be lifted up? Who is this Son of Man?"
We know that everything in the Law was written for those who are under its power. The Law says these things to stop anyone from making excuses and to let God show that the whole world is guilty.
Anyone who tries to please God by obeying the Law is under a curse. The Scriptures say, "Everyone who doesn't obey everything in the Law is under a curse."