The birth of John was important as an introduction to God's unfolding plan. Once again, God does something that doesn't seem to make sense: this is unfolded to a man who is immediately unable to speak of this grand unfolding. Maybe God has a sense of humor, or maybe God is content to allow things to unfold slowing, coming together in small revelations. Whatever the case, Zechariah had plenty of time to think about it as he was silent for a few months!