Who jesus is has been interpreted and developed throughout the centuries and it is impossible to divorce the message and teachings of Jesus from his identity.
i.e., we know what we know now, because ancestors in the faith believed in jesus as the christ, the son of God who is God.
his message is clearer because of who jesus was. we can more readily see the teachings (the most central teaching being the Kingdom of God-- which is different from "heaven") because of people's devotion to jesus as the risen christ
the divinity of jesus is the mystery of the incarnation. as i previously mentioned, the meaning of this aspect of the christian faith is still evolving
one part of it is: what does it mean to be human? God becomes human in order that humans can become like God. this is the heart of incarnation. we, as humans, learn best when we see things in the human form. God's love is made "in flesh" (incarnate)
so perhaps a corallary question is: what difference does my belief in jesus as the christ make in the way i live my life?
there are many "christian atheists" out there; people who proclaim their belief in christ, but live their lives as if God doesnt exist