Gregory the Dialogist

Fear came upon me and trembling, which made all my bones to shake. But when the mind is lifted on high, in proportion as it sees things higher above itself, the more terribly it trembles in itself. And hence it is fitly added, Fear came upon me and trembling, which made all my bones to shake. What is denoted by 'bones' but strong deeds? Of which also it is said by the Prophet, He keepeth all their bones. …

Morals on the Book of Job, Book V ↗

Thomas Aquinas

Second, he speaks of the disposition of the recipient, and so he adds, "Fear seized me." For men usually are struck with fear at the unusual, and so when someone has strange revelations, he suffers fear in the beginning. To show the greatness of this fear he adds, "and trembling," for the trembling of the body is an indication of the greatness of fear. …

Commentary on Job ↗