It is as high as heaven; what canst thou do? literally, heights of the heavens; what canst thou do? But the meaning is probably that expressed in the Authorized Version. God's perfectness is unattainable by man's thought, as the heights of the heavens are by his feet.
Deeper than hell; literally, than Sheol, or the receptacle of the dead (see the comment on Job 10:21). St. Paul speaks of the "deep things," or rather, "the depths" ( τὰ βάθη) of God (see 1 Corinthians 2:10).
What canst thou know? How small a part of the Divine nature can any man thoroughly comprehend and know!