Albert Barnes Commentary Isaiah 33:16

"He shall dwell on high; his place of defence shall be the munitions of rocks; his bread shall be given [him]; his waters shall be sure." — Isaiah 33:16 (ASV)

He shall dwell on high - See the margin. Heights, or high places, were usually places of safety, being inaccessible to an enemy. The sense here is that such a man as is described in (Isaiah 33:15) should be preserved from alarm and danger, as if his habitation were on a lofty cliff or rock. The particular and special meaning is that he should be safe from the anger, wrath, and consuming fire, which the sinner and the hypocrite dreaded (Isaiah 33:14).

The munitions of rocks - The literal translation of this phrase would be, ‘The strongholds of the rocks shall be his lofty fortress’ (compare the note at Isaiah 2:21).

Bread shall be given him - He shall be sustained, and his life shall be preserved.