Genesis 28:12

he dreamed . . . and behold a ladder--Some writers are of opinion that it was not a literal ladder that is meant, as it is impossible to conceive any imagery stranger and more unnatural than that of a ladder, whose base was on earth, while its top reached heaven, without having any thing on which to rest its upper extremity. They suppose that the little heap of stones, on which his head reclined for a pillow, being the miniature model of the object that appeared to his imagination, the latter was a gigantic mountain pile, whose sides, indented in the rock, gave it the appearance of a scaling ladder. There can be no doubt that this use of the original term was common among the early Hebrews; as JOSEPHUS, describing the town of Ptolemais (Acre), says it was bounded by a mountain, which, from its projecting sides, was called "the ladder," and the stairs that led down to the city are, in the original, termed a ladder (Neh 3:15) though they were only a flight of steps cut in the side of the rock. But whether the image presented to the mental eye of Jacob were a common ladder, or such a mountain pile as has been described, the design of this vision was to afford comfort, encouragement, and confidence to the lonely fugitive, both in his present circumstances and as to his future prospects.

— Jamieson-Fausset-Brown Commentary (public domain)