Brett explains why Jesus' death was the just payment for our sins.
Why did Christ need to die in order for us to be saved? Very simply, the consequence for sin is death. Romans 6:23 says, “For the wages of sin is death.”
Some may follow up and say, “Why is that the consequence? Why would that be the consequence that God has laid out?” I would say because sin is so serious. The consequence is death because sin is serious, and God takes sin seriously.
I think the judge analogy is helpful here. Think about a judge who has a criminal in front of him who has been convicted of a crime. Let's say the crime is murder, and the judge says, “I'm going to fine you $100, and then you can go. You're guilty, but just $100 fine, and you're free to go.” We would all look at that go, “Wait a second. That's not just!” Right? That's not justice. That punishment doesn't fit that crime.
In the same way, when we look at the issue of sin and the consequences, if God let us off the hook like that judge who let that murderer off the hook, justice would not be satisfied. Since the consequence of sin is death, death is what was required to satisfy the justice of God. That is why Jesus had to die to save us.