(Isa. 2:5)
Gospel light is the mental and spiritual enlightenment from God which enables men to receive truth and knowledge and gain salvation. Light is an attribute of Deity and shines forth from him; in him it is found in its fulness and perfection. . . .
Christ is the light of the world, and the gospel is his message of light and salvation to all men. . . . Where the gospel is there is light; where the gospel is not darkness prevails.
(Bruce R. McConkie, Mormon Doctrine, 2d ed. [Salt Lake City: Bookcraft, 1966], 444.)