This may not be theologically perfect, there may be holes in my logic. But this is just the simple way I understand the story of redemption, the way I understand our relationship with God and his son Jesus Christ.
God made Adam and Eve in His own image, and they lived with God in the Garden of Eden.
Then, in an act of rebellion against God, they ate the forbidden fruit and Sin entered the world.
This sin has become known as “human nature.” It is original sin. Meaning we are all born into sin, simply because we are human. Furthermore, we sin on a daily basis due to our flawed human ways.
But God still loves us. He wants to be with us. He created us.
However, God is also completely holy, which means he is without sin. And God is just, meaning that all of our sins must be paid for. And the price of sin is death.
In the Old Testament, the way that people asked God for forgiveness was through sacrifices of livestock or grain.
We as a people needed an acceptable sacrifice, to reconcile with God.
God knew that no person was perfect and holy enough to be an acceptable sacrifice for the sins of the world, so He sent His own Son to Earth.
Jesus Christ walked the Earth, fully human and fully God, and lived a perfect and blameless life.
When He died on the cross, He had done nothing that demanded judgement. God took all the punishment for the sins that we as humans have committed and poured out His righteous wrath on His blameless Son.
In that way, our sins were paid for.
Christ rose again, and ascended to heaven.
He paid the price for our sins as humans.
Because our sins were paid for, God in His infinite Holiness and Righteousness is able to live with us once again.
If we put our faith in what Christ did on the cross. If we believe in our hearts and confess with our mouths that Christ died for our sins, paid our price so that we could be with God, after our lives have ended, and we are being judged for our sin, God won’t see our faults and imperfections.
Instead, when He looks at us, He will see Jesus, and His perfect sacrifice.
So, because of Christ’s death on the cross, we can spend eternity with God.