Then Jesus said to them, “When you lift up the Son of Man, then you will know that I am He, and that I do nothing of Myself; but as My Father taught Me, I speak these things. (John 8:28)
Christ stated that His crucifixion will reveal who He is and that His death is in fact God’s plan for the salvation of the world. The crucifixion is part of God’s plan for our salvation. It is both a revelation of God’s total love for His creation and also God’s own understanding of justice. For as it turns out God’s love and justice are so intertwined as to be one reality.
And Paul went in, as was his custom, and for three weeks he argued with them from the scriptures, explaining and proving that it was necessary for the Christ to suffer and to rise from the dead, and saying, “This Jesus, whom I proclaim to you, is the Christ.” (Acts 17:2-4)
Why was it ‘necessary’ for Christ to suffer and die? Several ideas come into play here. Christ being God is not subject to death, and as a human He did not sin so He was not subject to a justice which says if you sin you will die. His death was necessary in order to accomplish the complete overthrow of sin and death from within Hades. To fill Hades with Himself, Christ had to go there but Hades as the place of the dead had no place for the eternal God the giver of life. Christ’s death fulfills whatever justice divine law demanded as well as bringing about the destruction of death and the salvation of humankind. Fr Matthew Baker writes:
… Athanasius argues that the death of Christ is salvific in part precisely because it is a fulfillment of divine justice. Athanasius asserts that human corruptibility and death are not only the ontological contents of sin but also that they are the implementation of divine law, as pronounced in Genesis: ‘of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat of it you shall surely die‘ (Genesis 2:17). God’s subsequent work of salvation cannot simply abrogate this law but must fulfill it, and that is why Christ had to die in order to bring about the forgiveness of sins and our salvation: ‘It was absurd,’ says Athanasius, ‘for the law to be annulled before being fulfilled.’ (ON THE TREE OF THE CROSS, p 69)
Christ dies for our sins since He Himself was sinless. He thus submits Himself to the requirements of the law that humanity living under sin will die. So Christ first fulfills the demands of the law and then annuls the demand, ending Death’s reign over humanity and creation. Christ fulfills the law and then proclaims His Lordship over the law in His resurrection, proclaiming to all the forgiveness of sins. Thus in becoming incarnate, Christ submitted Himself to all the aspects of being human, including death which had become part of the human condition due to human sin. The Incarnate God does not try to avoid any aspect of being human but rather takes them all upon Himself in order to redeem, heal and restore humanity to its proper relationship with death, the world and with the Holy Trinity.
And you, who were dead in trespasses and the uncircumcision of your flesh, God made alive together with him, having forgiven us all our trespasses, having canceled the bond which stood against us with its legal demands; this he set aside, nailing it to the cross. (Colossians 2:13-14)