Christmas and Easter, our two most important religious celebrations, serve as bookends for story of Jesus. They commemorate his birth and is death, both of which invoke the supernatural in the midst of the mundane and distinctly natural. The Christmas account, in its broadest context, spans a period of a few short years from the angelic announcement of his impending birth till Jesus and his family return from exile in Egypt. The story of Easter covers a mere week or so. Thus, invested in these two stories, we have only a very limited portion of Jesus' total time on earth.
One might reasonably wonder about the rest of the story of Jesus. Of what importance to our understanding of him are those portions of the Gospel accounts which don't deal directly with his birth or death. We know next to nothing about the life of Christ from early childhood till he was thirty years old. From age thirty until his death was a period of three or so years. What significance should we as followers of the Christ attach to the life lessons which he expounded to his disciples during that time? Are those lessons an integral part of what it means to be a Christian or are they merely incidental homilies, which are non-essential to knowing Jesus as the Savior of the world? One might conclude as much, given the tenets of Christian Orthodoxy in the traditional creeds.
No one can deny that the Easter story represents a climax in the life of Jesus and to the Bible as a whole. That being said, I still ask why is so little significance attached to the complete story of Jesus? In terms of what is included in the standard presentation of the " so called Gospel", the life of Jesus between the book ends is seemingly irrelevant. One must acknowledge his miraculous birth and resurrection to become a believer, but the rest of his story is apparently unimportant. One can remain largely ignorant of Jesus and still claim Christianity.
Jesus was the God-man. Our Christmas and Easter celebrations focus on his divinity. His life story, in the whole, focuses on his and our humanity and how that humanity is designed to reflect his divinity. When we only know the beginning and the end of the story and ignore what's in between, we easily miss the essential meaning. We have been fed some Cliff Notes on the story of Jesus. We now need to read the entire book for ourselves.