Isaiah 34:16

The verse is remarkable in several respects. It seems to be a solemn assurance that the foregoing prediction shall be fulfilled literally and down to the smallest details; and must therefore be addressed to a future generation of readers. This implies a view of the scope and functions of prophecy, which is not that of the older prophets. Further, the expression "book of Jehovah" appears to point to the existence of a prophetic canon; and the opening exhortation presupposes a habit of searching for evidences of the fulfilment of prophecy. All these circumstances would indicate a late date for the composition of this oracle. Some commentators, however, have sought to evade this interpretation by amending the text with the help of the LXX.; reading: "According to their number Jehovah calls them, &c." But the received text excites no suspicion.

the book of the Lord The immediate reference must be to the present prophecy, since there is no other which speaks of the desert creatures that are to possess the land of Edom. But the phrase is too pregnant to be used of a detached oracle; we must therefore conclude that it was destined to be incorporated in a collection of sacred writings.

my mouth … his spirit The change of person is harsh. Read either "his mouth" or (better) "the mouth of Jehovah" (LXX. has "Jehovah" alone).