Gregory the Dialogist

Who discovereth deep things out of darkness, and bringeth out to light the shadow of death. For when the several mystical truths are recognised in the secret words of the Prophets by them that believe, what else is it, than that 'deep things are discovered out of darkness?' Whence too 'Truth' Himself, speaking in parables to the disciples, saith, What I tell you in darkness, that speak ye in light. …

Morals on the Book of Job, Book XI ↗

Thomas Aquinas

As to those men who have no prestige, but live hidden in the lowest state, he then says, "he reveals those deep in darkness," that is, men placed in a lower state, who are unknown because of this, as though existing in darkness. He leads these to glory by revealing them to others. As to those that are thought foolish and ignorant, he then says, "he kindles the light where death's shadow lay," for the shadow of death seems to be ignorance or stupidity, since the living are distinguished from the nonliving especially by knowledge. …

Commentary on Job ↗