Job 36:12

But if they obey not, they shall perish by the sword, and they shall die without knowledge.

Job 36:12 belongs to Elihu's continuing speech in his argument. The speeches in the book of Job are not all necessarily true, and even a statement that is generally true can be misapplied to Job's particular suffering.

The verse sets forth God's way of dealing with people in order to save them, for He watches over the righteous and sets them on high. When they are bound in affliction He shows them their work and their transgression, opens their ear to discipline, and commands them to turn from iniquity. Those who obey and serve Him spend their days in prosperity and their years in pleasure, while those who refuse to obey perish by the sword and die without knowledge.

Rejecting the reproofs and pointed testimonies that God sends through His prophets to identify particular sins ends in ruin and certain destruction. It ends in losing present truth for infidelity and Spiritualism. Believing and obeying those testimonies brings cleansing through Christ's blood and prosperity.