Jesus is of first importance in God’s plan with humankind and the universe. Consider Colossians 1:15-20:
He is the image of the invisible God, the firstborn of all creation. (16) For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities–all things were created through him and for him. (17) And he is before all things, and in him all things hold together. (18) And he is the head of the body, the church. He is the beginning, the firstborn from the dead, that in everything he might be preeminent. (19) For in him all the fullness of God was pleased to dwell, (20) and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.
It was because of Jesus that God created the heavens and earth and the people on the earth. God’s plan with Jesus has been central to everything from the very beginning. He is the “firstborn from the dead”, so he is a new beginning in that sense too. Through Jesus, humankind is reconciled to God and therefore he is the fruition of God’s plan of redemption. When he establishes God’s kingdom on earth, Jesus will be the fruition of God’s plan for the world.
We see hints of this understanding in the following passages from the Revelation:
I am the first and the last, and the living one. I died, and behold I am alive forevermore
The words of the first and the last, who died and came to life.
I am the Alpha and the Omega, the first and the last, the beginning and the end.” (14) Blessed are those who wash their robes, so that they may have the right to the tree of life and that they may enter the city by the gates.
In 1 Corinthians 15:20-23, Paul speaks of Jesus being the first to rise from the dead and also the fruition of Jesus’ work when his followers will likewise rise from death to immortality:
But in fact Christ has been raised from the dead, the firstfruits of those who have fallen asleep. For as by a man came death, by a man has come also the resurrection of the dead. For as in Adam all die, so also in Christ shall all be made alive. But each in his own order: Christ the firstfruits, then at his coming those who belong to Christ.
When Jesus was crucified he said, “It is finished”, and bowed his head and died. Jesus had just finished his battle with sin/human nature. He had won the victory, as the writer to the Hebrews explains in Heb 2:14-15:
Since therefore the children share in flesh and blood, he himself likewise partook of the same things, that through death he might destroy the one who has the power of death, that is, the devil, (15) and deliver all those who through fear of death were subject to lifelong slavery.
The gospel can be succinctly stated as “Jesus is the first and the last.”