Seek ye out of the book of the LORD, and read: no one of these shall fail, none shall want her mate: for my mouth it hath commanded, and his spirit it hath gathered them.
Seek ye out of the book of the Lord - the volume in which the various prophecies and other parts of Scripture began henceforward to be collected together (Isaiah 30:8; Daniel 9:2). "Seek" (so Isaiah 8:16; Isaiah 8:20; John 5:39; John 7:52).
No one of these shall fail - of these prophecies (Matthew 5:18).
None shall want her mate - image from pairing of animals mentioned Isa. 35:15 ("mate"): no prediction shall want a fulfillment as its companion. Or rather, from the "them" which follows, referring to the animals about to be "gathered" in desolate Edom. '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 mouth ... and his spirit - such changes of person are frequent in Hebrew poetry.
Hath gathered them - the wild beasts.