Read with me once again Luke 1:19-25:
And the angel answered him, “I am Gabriel, who stands in the presence of God, and I was sent to speak to you and to bring you this good news.  And behold, you will be silent and unable to speak until the day that these things take place, because you did not believe my words, which will be fulfilled in their time.”  And the people were waiting for Zechariah, and they were wondering at his delay in the temple.  And when he came out, he was unable to speak to them, and they realized that he had seen a vision in the temple. And he kept making signs to them and remained mute.  And when his time of service was ended, he went to his home.  After these days his wife Elizabeth conceived, and for five months she kept herself hidden, saying,  “Thus the Lord has done for me in the days when he looked on me, to take away my reproach among people.”
Gabriel is a messenger sent directly from God Himself — the God that Zechariah served so faithfully for so long. The certainty of the prophecy that Gabriel gave was unmistakable — as if it would truly happen. When God gives a promise, it is a certainty. Zechariah should have known this, given the knowledge he had of the Scriptures and of the way God has worked out his story.
So now we see why this question that he asked in verse 18 is a question of unbelief. He know the Scriptures, he saw the confirmation — but there was that area of unbelief — that area where even Zechariah thought, “Even God can’t turn this area around.” Unbelief, dear friends, is saying, “God, you can’t handle this — the promises of my doubt and my anxiety and my fear offer me more than do your promises.
J.C. Ryle gives some good insight as to why the angel pronounced this punishment:
It was a chastisement suitable to the offence. The tongue that was not ready to speak the language of believing praise was struck speechless. It was a chastisement of long continuance. For nine long months, at least, Zechariah was condemned to silence, and was daily reminded, that by unbelief he had offended God
We forget that by nature we are rebels against God, don’t we? Most of the time, we simply see ourselves in light of others and don’t think we’re that bad. But the truth is that David said, “In sin did my mother conceive me” and that the writer of Hebrews notes, “It is destined for man to die once and after that, face the judgment” (Hebrews 9:27).
But I want to let you know that God out of love for us has provided a way out of that rebellion. You see, why was John born into the world? To be the forerunner of the Messiah! And in the midst of our rebellion —- whether high or low, rich or poor, priest or pauper — God sent Jesus into the world to become a man! Jesus never rebelled and was always obedient. He never walked in unbelief. Yet, as we celebrate Christmas, we must realize the reason why he came.
He came to die.
He came to die as a substitute for us rebels — he took the full penalty and rose again. And because he rose again, every rebel that lives right now has an opportunity for life. We know this from 1 Peter 1:3
Blessed be the God and Father of our Lord Jesus Christ! According to his great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead.
Now, will there be times when we fail, even though we are Christians and love Jesus? Yes. Will God make us bear the consequences of our sinful actions, even as Christians? Yes! But that does not mean he has abandoned us — it means that he loves us as a father loves his child. Hebrews 12:5-11
And have you forgotten the exhortation that addresses you as sons?
“My son, do not regard lightly the discipline of the Lord,
nor be weary when reproved by him.
 For the Lord disciplines the one he loves,
and chastises every son whom he receives.”
 It is for discipline that you have to endure. God is treating you as sons. For what son is there whom his father does not discipline?  If you are left without discipline, in which all have participated, then you are illegitimate children and not sons.  Besides this, we have had earthly fathers who disciplined us and we respected them. Shall we not much more be subject to the Father of spirits and live?  For they disciplined us for a short time as it seemed best to them, but he disciplines us for our good, that we may share his holiness.  For the moment all discipline seems painful rather than pleasant, but later it yields the peaceful fruit of righteousness to those who have been trained by it.
God is not leaving us, he is teaching us, refining us, shaping and fashioning us to trust his promises and His Word even when our guard is down, even when tragedy hits, even when trials come, even when temptation hits us hard — He’s our Father!