Jamieson, Fausset and Brown on Isaiah 34:16

16. book of the Lord--the volume in which the various prophecies and other parts of Scripture began henceforward to be collected together (Is 30:8; Da 9:2).

Seek--(so Is 8:16, 20; Joh 5:39; 7:52).

no one ... fail--of these prophecies (Mt 5:18).

none shall want ... mate--image from pairing of animals mentioned, Is 34:15 ("mate"); no prediction shall want a fulfilment as its companion. Or rather, "none of these wild animals (just spoken of) shall be wanting: none shall be without its mate" to pair and breed with, in desolate Idumea.

my ... his--Such changes of person are frequent in Hebrew poetry.

them--the wild beasts.