Why Did Jesus Have To Die On the Cross?
God is not only a loving God, but also a just God. God is the universal Judge. He is the only ‘umpire’ in the universe who can justly weigh the enormity of sin. Sin, any sin, amounts to lawlessness. (“Everyone who practices sin also practices lawlessness; and sin is lawlessness.” ~1 John 3.4)
God has declared that the just penalty of sin is death—not just physical death, but everlasting separation from Him. (Romans 6.23).
Now God in His love for His creatures planned a way whereby sinners (which all of us humans are) may be justly forgiven and accepted by God. Instead of us having to die for our own sins, by agreement with His Son, our Heavenly Father sent His Son into the world to save us (who trust in Him) from the penalty of our sins. Somebody has to pay the price of our transgression. Justice has to be served.
A just God could not just say, “I’m OK, you’re OK.” The death penalty had to be executed for the sake of the integrity of divine justice. Either we die for our own sins or we allow Jesus Christ to die (legally) in our place. (“For, [God the Father] made Him [the Son] who knew no sin [was a sin-free being] to be [as it were] sin on our behalf, that we might become [cleared of sin guilt, legally speaking and therefore as] the righteousness of God in Him.” ~2 Corinthians 5.21.)
A spirit could not make this atonement, only a physical being. So the Son of God became also a son of man (it is called the incarnation) so that He in our place might be put to death as our legal Substitute. (“For God so loved the world that He gave His only begotten [or unique] Son that whoever believes in Him might not perish [as otherwise we surely would] but have eternal life.” ~John 3.16; “He who believes in the Son has eternal life; but He who does not obey the Son [i.e. following Him in faith] shall not see life, but the wrath of God abides on Him.” ~John 3.36)
Now that explains why Jesus had to die. But how could the death of a single Being be a just settlement of all people? Is this not just a legal fiction? No. Jesus Christ qualified to atone for the sins of all men because 1) He was sinless, a Lamb without defect and 2) He was the Son of God incarnate and therefore a Being of infinite worth whose self-sacrifice was in the eyes of God of sufficient worth to cover or atone for the guilt of all mankind who would receive His atonement. (…”you were not redeemed with persishable things like silver and gold from your futile way of life inherited from your forefathers, but with precious blood, as of a lamb unblemished and spotless, the blood of Christ.” ~1 Peter 1.18-19).
Finally, why did Jesus have to die on a cross? It was ordained as a fulfillment of biblical prophecy. In John 3.14 Jesus said, “.And as Moses lifted up the serpent in the wilderness, even so must the Son of Man lifted up;…” In chapter 8.28 He again anticipated His death on the cross, saying, “When you lift up the Son of Man. . .” He used the same expression of the cross in John 12.32 and 34. It went down exactly as He predicted and that was the plan of God.
That is not all. “Christ redeemed us from the curse of the Law (i.e. the penalty of sin], having become a curse for us [dying in our stead]—for it is written, ‘Cursed in every one who hangs on a tree—“ ~Galatians 3.13 Such a curse was implanted back in Deuteronomy in anticipation of Christ’s execution on a tree.