D&C 84

 As we are taught concerning the Spirit of Jesus Christ or the Light of Christ, we learn - 

"...the Spirit giveth light to every man that cometh into the world; and the Spirit enlighteneth every man through the world, that hearkeneth to the voice of the Spirit."  (Doctrine and Covenants 84:46)

I note that enlightenment only comes to those that hearken to Light of Christ.  And thus we learn - 

"...the whole world lieth in sin, and groaneth under darkness and under the bondage of sin.

50 And by this you may know they are under the bondage of sin, because they come not unto me.

51 For whoso cometh not unto me is under the bondage of sin."  (Doctrine and Covenants 84:49–51)

Thus, by the Lord's definition - 

"...by this you may know the righteous from the wicked..."  (Doctrine and Covenants 84:53)

Obviously, this includes members of the Church.