Then an angel of the Lord appeared to him, standing at the right side of the altar of incense. When Zechariah saw him, he was startled and was gripped with fear.
Zechariah was a faithful man, one who waited patiently for the coming Messiah. But he was still startled and even fearful when the angel appeared.
This is understandable, for no one had heard from the Lord in over 400 years. No angels had appeared to the priest or to the people. So when one finally appeared, even this good man did not know what to do.
Most of us have trouble waiting. And when the Lord finally speaks or acts we are also surprised—with or without the angel. As often as not, the message is unbelievable.
All we have to do is believe it.