“Fall upon us!” they were saying to the mountains and the rocks. “Hide us from the face of the One who sits on the throne, and from the anger of the lamb! The great day of their anger has come, and who can stand upright?”
If your boss, teacher, spouse, or a police officer wants to have a word with you, it can be terrifying if you realize that you have not done what you’re supposed to do, or crossed them, or broken the law.
Encountering God can be scary for those who have lived their own way, without much or any consideration for God.
And this is not due to sin per se, because sin has been dealt with through Jesus Christ. But because of not accepting the wonderful gift of that chasm being bridged, so that we may enjoy unbroken fellowship with God, it will be terrifying to meet God—really for the first time—with nothing to say for yourself, nowhere to hide, fumbling for the words to explain why you did not live in close connection with the One who gave you your very life, the kindest, most loving God who has given you every chance to live a meaningful and joyful life in relationship with Him everyday.
In that situation, even a lamb is scary as hell.