Albert Barnes Commentary Daniel 4:5

"I saw a dream which made me afraid; and the thoughts upon my bed and the visions of my head troubled me." — Daniel 4:5 (ASV)

I saw a dream - That is, he saw a representation made to him in a dream. There is something incongruous in our language in saying that one saw a dream.

Which made me afraid - The fear evidently arose from the apprehension that it was designed to disclose some important and solemn event. This was in accordance with a prevalent belief then , and it may be added that it is in accordance with a prevalent belief now. There are few persons, whatever may be their abstract belief, who are not more or less disturbed by fearful and solemn representations passing before the mind in the visions of the night. Compare Job 4:12-17 and Job 33:14-15. So Virgil (Aeneid 4.9):

“Anna soror, quae me suspensam insomnia terrent!”

And the thoughts upon my bed - The thoughts which I had upon my bed; that is, in my dream.

And the visions of my head - What I seemed to see. The vision seemed to be floating around his head.

Troubled me - Disturbed me; produced apprehension of what was to come, of some great and important event.