Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 1:65-66

“As at the silence of Zacharias the people marvelled, so likewise when he spoke. Hence it is said, And fear came upon all; that from these two circumstances all might believe there was something great in the child that was born. But all these things were ordained, to the end that he who was to bear witness of Christ might also be esteemed trustworthy. Hence it follows, And all they that heard them laid them up in their heart, saying, What manner of child, &c.”