John Wesley on Job 4:13

In thoughts - These thoughts arose from the visions of the night, which it is probable he had seen before. Visions differed from dreams herein, that God imparted his mind to men in dreams when asleep, but in visions, when they were awake. And these visions sometimes happened by day, but most frequently by night. Sleep - In the dead of the night, when men usually are in a deep sleep; though Eliphaz was not now asleep.