In religion a revelation is the revealing or disclosing of information, usually in a dramatic way, by God.
Christians believe that God reveals his will to humanity through the words of the Christian Bible, which, although they had human authors, were inspired by God.
Christians also believe that God revealed himself through the life, death and resurrection of his Son Jesus, the promised Messiah.
John's Gospel does not contain a birth story, but it does try to explain the incarnation as a revelation: "No one has ever seen God; but God's only Son, he who is nearest to the Father's heart, he has made him known." (John 1.12-13)