פירוש על ברכות 108:1

The first word is read ashad instead of eshed, "the slopes of," in the Biblical text. As rendered here, the verse means that the hills on the Ar side of the valley inclined towards the hills on the Moab side, so that the Amorites were crushed in between. Wiesner, p. 122, points out that this Aggadah seems to have been known to the author of the Vulgate: Unde dicitur in libro bellorum Domini : Sicut fecit in Mari rubro, sic faciet in torrentibus Arnon, Scopuli torrentium inclinati sunt ut requiescereut in Ar, et recumberent in finibus Moabitarum.