Theophylact of Ohrid
Catena Aurea · Lukasevangelium 1
And Zacharias said unto the angel, Whereby shall I know this? for I am an old man, and my wife well stricken in years. And the angel answering said unto him, I am Gabriel, that stand in the presence of God; and am sent to speak unto thee, and to shew thee these glad tidings. And, behold, thou shalt be dumb, and not able to speak, until the day that these things shall be performed, because thou believest not my words, which shall be fulfilled in their season. And the people waited for Zacharias, and marvelled that he tarried so long in the temple. And when he came out, he could not speak unto them: and they perceived that he had seen a vision in the temple: for he beckoned unto them and remained speechless.
But Zacharias beckoned to the people, who perhaps enquired the cause of his silence, which, as he was not able to speak, he signified to them by nodding. Hence it follows, And he beckoned to them, and remained speechless.