This posting will be focused on the gospel proper to December 19th, rather than the gospel for the Fourth Sunday of Advent (especially since it is the same gospel we heard yesterday).
Today the gospel presents us with the scene of the Annunciation to Zechariah. Zechariah, we are told, was praying for a son, but now in his old age he no longer believed it possible. The angel Gabriel appeared and told him that his prayer would be answered, God was going to give him exactly what he wanted, but Zechariah strangely, still did not believe it could happen, and so was rendered speechless until after his son's birth. How often do we have to accept those times when God sends us trials, when God answers our prayers but the answer is "no", but in those rare moments, when God does say "yes", when God gives us exactly what we want, why do we still have trouble, why do we still fail to believe? Is it just our own weak faith? Is it just part of our human nature to question, to doubt, to wonder why we don't get what we want, and to doubt even more when we get it? I don't claim to have an answer for this one, but the question is certainly worth pondering.