Hast thou not known?... — The questions are parallel to those of Isaiah 40:21, but are addressed to the Israel of God, rather than, as those were, to mankind.
The Creator of the ends of the earth. — The word emphasises the thought that the whole earth, from the Euphrates to the “islands” of the sea, is subject to the power of the Eternal.
Fainteth not, neither is weary?... — Had Isaiah learnt to feel that even his own phrase as to men “wearying God” (Isaiah 7:13) was too boldly anthropomorphic, and might, therefore, be misleading?
No searching of his understanding. — The words come, like so many others like it, from Job (Isaiah 5:9; Isaiah 9:10), and must have been in St. Paul’s mind as he wrote Romans 11:33.