Many shall be purified, and made white, and refined; but the wicked shall do wickedly: and none of the wicked shall understand; but the wise shall understand.
Read Chapter 12
Aquinas Study Bible
AD 2017
And if the prophet himself heard and did not understand, what will be the case with those men who presumptuously expound a book which has been sealed, and that too unto the time of the end, a book which is shrouded with many obscurities? But he comments that when the end comes, the ungodly will lack comprehension, whereas those who are learned in the teaching of God will be able to understand. (St. Jerome)