Nightmares

Nightmares, whether it's a dream or reality, it seems to be incongruence with the things I believe. It wasn't a nightmares that is unpredictable, but nightmares that you always expect it to happen. It was something that you have to struggle with all the time.
It isn't the things that you always pray for, but things that you will normally pray of.

Are nightmares worries of our daily life, or it's just a shadow of God's prophecies?