When God and His Son sat down to discuss how they were going to create a new universe in which humans could live forever in perfection, they also decided to create a complex (to us) plan to return us to Their favor when we turned away from Them. The plan culminated in the Son of God becoming the Son of Man, defeating death and evil with his own death.
There were and are many actors in the drama that is our salvation. Adam, Eve, Noah, Abraham, Isaac, Jacob, David, Isaiah, Daniel, Mary, Elizabeth, John, and thousands more played key roles. John was on the stage for a short time, at least in our records, but that does not diminish his importance. He introduced the Messiah, the Son of Man.
The faith of Abraham, the devotion of David, the love of Mary fell short of salvation. As great as they were, they could not save themselves, let alone anyone else. The Son of Man alone could do that.
When God and the Son planned, they knew that sin would enter the world, so they planned an escape route for us. The Son agreed to take on the role of the sacrificial Lamb, so that his blood could substitute for the blood we would need to shed. We have all been convicted of crimes against God and the punishment is death. Our lawyer stepped in to die for us so that we may live.
God created a universe knowing that it would wobble off course and need correction. He knew his humans would fail to be true sons, so he also created a way to save us from ourselves. He chose us and will not let us go without a struggle.
Be righteous and do good.