Hope is the traditional theme for the first week of Advent.  We see the hope of Christmas, the Messianic hope, throughout the Old Testament starting in Genesis 3.  Biblical hope is confident expectation based on scripture and God's character.  After the resurrection of Jesus, the New Testament writers continue to look forward in hope because God's kingdom has not yet come in fullness.  However, our hope continues to be confident, based on the promises of scripture and God's character, that he cannot lie.