Luke 1:1-38 https://www.biblegateway.com/passage/?search=Luke+1%3A1-38&version=NIV
If Zechariah was trending on twitter for the events in these verses, it might involve tweets looking a bit like this:
Lowkey sympathy for Zak, massive congrats on Liz’s pregnancy! #harsh #dumbnotdumb #letthemanspeak #zechariahthepriest
His punishment for unbelief wasn’t devastating, so we’re not overly troubled by it. But it’s easy to feel like he was harshly dealt with. If we’re honest, that’s probably a sensation, feeling, thought or opinion that frequently crosses our minds when we read how God treated people.
It started well: one day, well into Zechariah and Elizabeth’s old age, an angel turns up – in startling fashion – and tells him that his prayers have been answered: they WILL, in fact, have a child. Not only that, but their child will bring them joy, be famous, bring many people back to God, get people ready for God, will – uniquely in human history – be imbued with the Holy Spirit from birth, and will live powerfully like Elijah (one of the three most celebrated Hebrew men of the previous 2,000 years). The angels specifically cites passages in Malachi (3:1 & 4:5-6) that will be fulfilled in the life of his son.
Essentially, the angel Gabriel told Zechariah that his son would be one of the most important people ever.
The response of the faithful priest, the god-fearing, praying man who had served God well for several decades, was…unbelief. He didn’t ask who the angel was or who he represented – that much was clear to him. However, like the faith-lacking Gideon before him, Zechariah just wouldn’t believe what God was telling him, because it seemed impossible. Not that his son would be one of the most important people in history, but that he would have a son at all. The creator of the entire universe from nothing, told Zechariah that he was going to ensure Elizabeth conceived in her old age…and Zechariah wasn’t buying it.

To say that it was an odd reaction for Zechariah to have is polite. It was a terrible reaction. A terrible, ungrateful, faithless response to a staggeringly generous and utterly doable promise from God.
A terrible, ungrateful, faithless response much like how we respond to God on a regular basis. We have an entire catalogue of promises from God, for wisdom (James 1), for his presence with us at all times (Matt 28:20), of forgiveness without guilt (Romans 8:1), and so on. And yet, so often, even though we probably don’t say it out loud like Zechariah did, we effectively say the same thing.
It was God’s mercy that struck Zechariah dumb because it was un unpleasant – and memorable – reminder for him that God can do anything and God keeps all his promises.
Ask God to help you call to mind the promises of his that you have neglected, ignored, forgotten or don’t’ really believe. Repent of your lack of faith, ask for more faith, and thank God for the joy that can come from holding on to his promises.