Why the blood? Why the Cross? Why the Resurrection?
Let me approach your questions from several angles. If the question is, “Why is blood involved in salvation?” then the ultimate answer is because God sovereignly choose to design the universe so that blood was necessary to propitiate His wrath against human sin. The precise reason why God chose to do this is, as best I can tell, one of the “secret things” that belong to the Lord (Deut. 29:29).
If the question is, “Why did Jesus’ death have to be a bloody death, as opposed to a bloodless death?” then Leviticus 17 gives us at least part of the answer. Leviticus 17:10-14 explains why blood was not to be eaten (see also Gen. 9:4; Acts 15:20). In verse 11 God says, “For the life of the flesh is in the blood, and I have given it to you on the altar to make atonement for your lives; for it is the blood by reason of the life that makes atonement.”
Notice first that the God gave the Israelites blood on the altar to make atonement for their lives. In other words, blood is not inherently able to make atonement. It is only used in atonement because God ordained that it be used. Second, notice that God says the “life of the flesh is in the blood.” Apparently, it is because life is in the blood that blood is chosen to atone for our lives. Life for life. And that brings us to the issue of sin’s wages.
God’s holy and just nature demands that a sinner must die for his sin. However, in His loving justice and wise mercy, God determined that His wrath against sin could be satisfied, if His Son would become the second Adam, live sinlessly, and give his life by dying in our place. This plan that Jesus should give his life for us was in place “from the foundation of the world” (Rev. 13:8). In fact, Jesus’ sacrifice was the reality that the OT sacrifices portrayed and pointed toward. The point that God appears to be making in Lev. 17:11 is that blood must be shed for one life to substitute for another life because life is in the blood. This seems to be underscored by the last phrase in v. 11: “it is the blood by reason of the life that makes atonement.”
In order for Jesus to lay down his life for us and provide atonement for our lives, he had to shed his blood in death. Thus, “there is no forgiveness of sins without the shedding of blood” (Heb. 9:22). For sin to be forgiven, life must be given. Life is in the blood, therefore, blood must be shed.
Why the cross? I assume you mean why did Jesus have to die on a cross as opposed to dying anywhere else? I think Paul gives us the answer in Galatians 3:13, “Christ redeemed us from the curse of the Law, having become a curse for us– for it is written, “Cursed is everyone who hangs on a tree.” Christ’s crucifixion on the “tree” was necessary to show that he had taken the law’s curse on Himself.
Under the Mosaic Law this was the fate of criminals whom God had cursed (Deut. 21:23). God did not curse Christ because He hung on a tree, but Christ hung on a tree because He had taken the curse and its accompanying penalty of death on Himself.
Why the resurrection? If you mean why did the resurrection have to take place, I can think of three reasons immediately.
- First, because Jesus said it would prove that He was the Son of God (John 2:19-21; Matt. 17:22-23).
- Second, because it demonstrated that Jesus had conquered death, our greatest foe. Jesus proclaims in Revelation 1:17-18 “Do not be afraid; I am the first and the last, and the living One; and I was dead, and behold, I am alive forevermore, and I have the keys of death and of Hades.
- Third, Romans 4:25 says that Jesus was “raised for our justification.” The only way we could be justified is by being united with Christ. If Christ did not rise from the dead, we could not be united with him and thus could not be justified. Our justification rests entirely upon our union with Jesus.
I hope this helps.