Psalms 148:4 - Ellicott's Commentary On The Whole Bible

Heavens of heavens. — See Psalms 68:33, and references. Before passing downwards to the earth the invocation pauses to combine all the heights, which have been before addressed in the expression which denotes their position relatively to the earth; the highest heaven of all, and then the world of water which, in the Hebrew conception of the Cosmos, was supposed to be the foundation, while itself rests on the firmament or heavenly vault. (See Psalms 104:3.)