Commentaries
33:21-29 Those are unteachable indeed, who do not learn their dependence upon God, when all creature-comforts fail. Many claim an interest in the peculiar blessings to true believers, while their conduct proves them enemies of God. They call this groundless presumption strong faith, when God's testimony declares them entitled to his threatenings, and nothing else.
27. shall fall by the sword—The very object of their confidence would be the instrument of their destruction. Thinking to "stand" by it, by it they shall "fall." Just retribution! Some fell by the sword of Ishmael; others by the Chaldeans in revenge for the murder of Gedaliah (Jer 40:1-44:30).
caves—(Jud 6:2; 1Sa 13:6). In the hilly parts of Judea there were caves almost inaccessible, as having only crooked and extremely narrow paths of ascent, with rock in front stretching down into the valleys beneath perpendicularly [Josephus, Wars of the Jews, 1.16.4].