1:19-22 — The angel answered, "I am Gabriel. I stand in the presence of God, and I have been sent to speak to you and to tell you this good news. And now you will be silent and not able to speak until the day this happens, because you did not believe my words, which will come true at their proper time."

Meanwhile, the people were waiting for Zechariah and wondering why he stayed so long in the temple. When he came out, he could not speak to them. They realised he had seen a vision in the temple, for he kept making signs to them but remained unable to speak.

The angel's retort to Zechariah's unbelief is sharp. In three terse sentences he asserts his identity ("I am Gabriel"), his office ("I stand in the presence of God") and his mission ("I have been sent to speak to you . . ."). In essence Gabriel says, "If you have understood who I am, my office and what I have been appointed to do, you will know that I have no time for tomfoolery."

For his unbelief, the angel sentences Zechariah to a strong dose of silence which, he clarifies, means Zechariah will not be "able to speak until the day this happens." As David Gooding observes, there is sound logic to this sentences:

The action was neither vindictive nor arbitrary. In a few minutes Zechariah was expected to go outside and, as priest on duty for the day, in God's name pronounce God's blessing on the waiting people. But a priest who cannot believe the authoritative word of an angel of God, because he cannot accept the possibility of divine intervention to reverse the decay of nature, has lost faith in the basic principle of redemption. Without redemption, he has no gospel. Without a gospel, any blessing he pronounced upon the people would be the emptiest of professional formalities. If Zechariah could not believe the angel's gospel, it were better that he did not pretend to bless the people. Fittingly the angel struck him dumb.

David Gooding, According to Luke, 36.

In addition to the punitive purpose, the silence may also serve two other purposes. First, it serves to confirm for Zechariah the truthfulness and certainty of what Gabriel has pronounced, and second, it keeps God's plan confidential to those involved until the appropriate time.

The angel's sentence took immediate effect, and when he finally did come out and having been struck dumb, he was unable to to pronounce the priestly blessing on the people as he was supposed to. Unable to explain his situation—would he have told them, if he was able to, about his unbelief?—they surmised he had had a vision from what unintelligible signs he made. If only they knew the momentous tidings that attended their worship that day.