When they experienced a vision and the call of God the Old Testament prophets, and others, were left quite shaken (to say the least).
A few examples:
Isaiah: The word of God came with God's strong hand upon him (Is 8:11), cramps seized his loins & twilight became a horror to him (Is 21:3-4)
Daniel: Exhausted and sick for several days with the colour drained from him (Dan 8:27; 10:8)
Habakuk: was left heart pounding, lips quivering, his bones 'decayed' within him and he was trembling (Hab 3:16)
Ezekiel: overwhelmed to the extent that he was unable to speak for several days (3:15)
The prophets then brought a message that has spoken through the ages; messages from God that are still speaking today about the glory of the creator God.
I wonder sometimes if I/we are 'really' meeting with, seeing and experiencing the call of God through His Word or any other means.