Jamieson, Fausset and Brown on Genesis 28:18-19

18-19. Jacob set up a stone, etc.--The mere setting up of the stone might have been as a future memorial to mark the spot; and this practice is still common in the East, in memory of a religious vow or engagement. But the pouring oil upon it was a consecration. Accordingly he gave it a new name, Beth-el, "the house of God" (Ho 12:4); and it will not appear a thing forced or unnatural to call a stone a house, when one considers the common practice in warm countries of sitting in the open air by or on a stone, as are those of this place, "broad sheets of bare rock, some of them standing like the cromlechs of Druidical monuments" [Stanley].