Why was Jesus Crucified? Chuck Swindoll puts it this way, "By shedding His blood on the cross, Jesus took the punishment we deserve and offered us His righteousness. When we trust Christ for our salvation, essentially we are making a trade. By faith, we trade our sin and its accompanying death penalty for His righteousness and life.
In theological terms, this is called "substitutionary atonement." Christ died on the cross as our substitute. Without Him, we would suffer the death penalty for our own sins....
The Crucifixion of Jesus Christ - Death & Resurrection
In the inner court of the temple in Jerusalem, in the Holy of Holies, was the Ark of the Covenant. That was where the high priest would go once a year to offer atonement for the sins of the people. A veil, a very thick, woven curtain, separated the Holy of Holies from the rest of the temple.
The key to understanding the cry of Jesus from the cross is found in Paul's letter to the Galatians: "Christ redeemed us from the curse of the law by becoming a curse for us, for it is written: ‘Cursed is everyone who is hung on a tree'" (Galatians 3:13, NIV).
When God gave Moses and Aaron the rules for the Passover, some might have sounded unconventional—for example, the clear prohibition against breaking any bones of the lamb that was sacrificed and eaten by each household. Why did God insist on this?
That question has echoed down the ages. Did the Jews kill Jesus? Was Pilate guilty of murder? What about Caiaphas the high priest and Herod the king? What role did the centurions play? What about the crowd shouting, “Crucify him! Crucify him!”?