Ahaz, Paul and Joseph were three men up against the inscrutability of God. One was a king whose rebellion exhausted God and led him to the brink of disaster and whose heart shook like a tree in the wind. One was a zealous Jew whose fidelity to the God of his ancestors made him a murderer and blinded him to the possibility that God's coming might not be as he anticipated.
There's a phrase tucked away in Psalm 146 that provides the basis for our Advent hope: God "keeps his promise for ever." Without that assurance there is no hope and no sense in Advent. Our hope is in God.
Advent is a time to recall that it is not our own unpredictable desire for God that shapes our history, but God's faithfulness. Yes, Advent is a season to make our longing conscious. But primarily it is a season to become more aware of the God who creates that longing in us.