Luke 1:12 “And when Zacharias saw him, he was troubled, and fear fell upon him.”
Why the troubling first and the fear after? Well, rather than being spooked he just couldn’t believe his eyes at first. The angel didn’t sneak up on him. He was in the temple, so his awareness of his surroundings was on overdrive to say the least. So he wasn’t scared at first. He was puzzled, flabbergasted, surprised, but not scared. Then, once he began to realize his senses were not decieving him, the fear set in. Now he was afraid because he knew what he was seeing. He understood that this could be bad news for him. The angel could have been sent to slay him for not being holy as he worked in the temple, or whatever.
Heavenly Father, thank You for releaving our fears. You could make Your work with us more fearsome, but You do not. You remember we are but dust. You are kind and faithful. We will praise You forever for the beauty of Your plan! In the Name of the Lord Jesus Christ I pray and praise You, Amen.