Nothing is impossible with God
What really stands out to me in this wonderful passage is what Gabriel says to Mary. It sounds impossible -- a young woman having a child though she has not known a man, that this child would be the Son of God, the Savior of the world! No wonder Mary was confused and perhaps even a little doubtful. But the angel tells her, "Nothing is impossible with God." And as a sign of that, he told her about Elizabeth being pregnant, Elizabeth who had long been unable to have a child and was past child-bearing age. But nothing is impossible with God.