To dwell in the cliffs of the valleys - They were obliged to take shelter in the most dangerous, out-of-the-way, and unfrequented places. This is the meaning.
To dwell in the cliffs of the valleys - The word here rendered “cliffs” (ערוץ ‛ârûts ) denotes rather “horror,” or something “horrid,” and the sense here is, that they dwelt in “the horrer of valleys;” that is, in horrid valleys. The idea is that of deep and frightful glens, where wild beasts ranged, far from the abodes of men, and surrounded by frightful wastes. The word rendered “valleys” (נחל nachal ) means properly a brook, stream, water-course - what is now called a wady; a place where the winter torrents run, but which is usually dry in summer; see the notes at Job 6:15.
In caves of the earth - Margin, as in Hebrew “holes.” Septuagint “Whose houses are - πρῶγλαι πετρῶν trōglai petrōn - caverns of the rocks;” that is, who are “Troglodytes.” Caves furnished a natural dwelling for the poor and the outcast, and it is well known that it was not uncommon in Egypt, and in the deserts of Arabia, to occupy such caves as a habitation; see Diod. Sic. Lib. iii. xiv. and Strabo, Lib. 16,
And in the rocks - The caverns of the rocks. Dr. Richardson found a large number of such dwellings in the vicinity of Thebes, many of which were large and beautifully formed and sculptured with many curious devices. Mr. Rich, also, saw a large number of such caves not far from Mousal. Residence in Koordistan, vol. ii. p. 94.