It's pretty difficult for even the savviest of Bible scholars to adequately get their arms around all of the ramifications of the death of Christ - entire books are written just about the cross. For example: just think for a moment about how the cross demonstrates the depth of God's love for us - He gave His only begotten son. I try to imagine giving my daughter's life for an enemy; for someone that has deeply hurt me or my family; for a rapist...and the thought of doing that takes my breath away.
Why did God the Father will the death of His only beloved Son - and in such a painful and shameful way? There're so many reasons. The Father "laid on him the iniquity of us all" (Isaiah 53:6) - what a thought; Jesus' death was vicarious (undergone in our place) and atoning (securing remission of sins for us and reconciliation to God); it was a sacrificial death, fulfulling the principle of atonement taught in connection with the Old Testament sacrifices: "without the shedding of blood there is no forgiveness of sins" (Leviticus 17:11 and Hebrews 9:22).
As the "last Adam," the second man in history to act on all of mankind's behalf, Jesus died a representative death. As a sacrificial victim who put away our sins by undergoing the death penalty that was our due, Jesus died as our substitute. By removing God's wrath against, us for sin, His death was an act of propitiation (Romans 3:25 & 1st John 2:2; 4:10). "Expiation" the word that signifies "that which puts away sin," is only half the meaning. By saving us from slavery to ungodliness and divine retribution for sin, Jesus' death was an act of redemption (Galatians 3:13; Ephesians 1:7 & 1st Peter 1:18-19). By mediating and making peace between us and God, it was an act of reconciliation (Romans 5:10-11). His death opened the door to our justification (pardon and acceptance) and our adoption to becoming God's sons and heirs (Romans 5:1, 9 & Galatians 4:4-5).
This happy and blessed relationship with our Maker, based on and sealed by blood atonement, is the "New Covenant" of which Jesus spoke in the Upper Room (1st Corinthians 11:25 & Matthew 26:28) - and the same Covenant that secures us a new life!
Pastor John