1 Peter 3:18 For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit.
What Jesus did for us by His death and resurrection was bring us to God. This was what God promised to His separated people, what Jesus accomplished for us, and what will be completely fulfilled at Christ’s Second Coming.
We are born blind, dead, and enemies of God. Sin brings death; death is separation, separation from God. God created us for Himself, out of love, so that He could have a reciprocal, loving relationship with us. But we spurned that love and rejected God by our self-centered Sin. Therefore, death came upon all men, and all people come into this world dead in sin and separated from the God who made them for Himself.
But the Lord God didn’t give up on His original purpose. He injected Himself into human history, into our lives, in the person of His Son to redeem us from Separation by becoming separated for us. Through Christ we are reconciled to God. We are brought back to God where we belong. And that is the only place in the created universe where we will find rest, peace, joy, love, satisfaction, meaning and purpose.
As Christians, we live in two worlds at the same time: one world without God one world with God. We know which is better beyond a doubt; however, our sin continually separates us, the world deceives us and pulls us back, and our own flesh doubts God. But we come back to God by daily and weekly repentance and faith in forgiveness through the Gospel. We need this promise, that Jesus brings us to God and keeps us there forever, whenever we sense the symptoms of separation and death. We suffer in sins; Jesus suffered for sins to bring us to God, where there is no sin or death.