2 Nephi 30

Nephi warns -

"...the time speedily cometh that the Lord God shall cause a great division among the people, and the wicked will he destroy; and he will spare his people, yea, even if it so be that he must destroy the wicked by fire."  (2 Nephi 30:10)

In modern day, the Lord said -

"And until that hour there will be foolish virgins among the wise; and at that hour cometh an entire separation of the righteous and the wicked; and in that day will I send mine angels to pluck out the wicked and cast them into unquenchable fire."  (Doctrine and Covenants 63:54)

This division will be between the foolish and the wise.  It is difficult to determine either but it is may opinion the "believers" that are striving to live what they have been taught may be considered the wise.