1 Nephi 12:16-18
16. And the angel spake unto me, saying: Behold the fountain of filthy water that thy father saw; yea, even the river of that he spake; and the depths thereof are the depths of hell.
17. And the mists of darkness are the temptations of the devil, that blindeth the eyes, and hardeneth the hearts of the children of men, and leadeth them away into broad roads, that they perish and are lost.
18. And the large and spacious building, that thy father saw, is vain imaginations and the pride of the children of men. And a great and a terrible gulf divideth them; yea, even the word of the justice of the Eternal God, and the Messiah who is the Lamb of God, of whom the Holy Ghost beareth record, from the beginning of the world until this time, and from this time henceforth and forever.
A common thread runs through the symbolism of each of the bad things the angel explained to Nephi. That thread is a persistence in insisting that things are real when they are not real. Jeremiah accused the children of Israel of the same sort of thing: “How shall I pardon thee for this? Thy children have forsaken me, and sworn by them that are no gods” (Jeremiah 5:7). That same sense, that the pagan gods are not gods but just bits of wood or metal, is also found in Isaiah: “All nations before him are as nothing; and they are counted to him less than nothing, and vanity” (Isaiah 40:17).
Both Jeremiah and Isaiah are accusing the Israelites of the same thing: Not that they are swearing by or worshiping a god that is false, but that they are swearing by and worshiping a god that has no reality at all.
This is like the angel’s explanation to Nephi: “The mists of darkness are the temptations of the devil, that blindeth the eyes, and hardeneth the hearts” (1 Nephi 12:17). Blindness of this sort is never perceived as real blindness. It mocks the light and “loves darkness rather than light.” Here again the problem is one’s refusing to see the reality of the light and insisting that a bad thing is actually good, turning from reality to a fiction and using the fiction to obscure the reality. Evil is real, but the rationale that is used to justify it is an illusion.
Hardness of heart is the same thing. The refusal to know binds us in “the chains of hell” (Alma 12:11). Having a hard heart is refusing to hear, as being in the mists of darkness is refusing to see. It is turning from the reality of the things of God to a fiction that are the “philosophies of men,” making the fiction the path of one’s life and refusing to recognize the light that is real.
“The large and spacious building…is vain imaginations and the pride of the children of men.” Everything is this world, even our own bodies testify to us that they are tentative. “Vain” simply means things that have no consequence, artificial things (money, a fancy car, a big house, power, the ability to exercise authority over other people) that are transient in their nature, temporary in their worth. They seem as real as our experience in this world but are not real in terms of our being able to sustain their existence, or they ours, beyond the this life.
Not everything in this world lacks permanence. One’s house is temporary, and will decay into the elements from which it came, but inviting someone home to dinner may have eternal ramifications. The car is temporary, but giving someone a ride when he needs to get somewhere is real. Power and authority are very temporary, but blessing someone’s life is very real. Real things are things that will last through eternity.
“Vain imaginations” is a kind of redundancy. It suggests things that have no reality but that are imagined to be of worth. Pride is about things that have no reality but that are imagined to be of worth, except “pride” is one’s attitude about the imaginary things with which we decorate ourselves (like the emperor’s clothes) as opposed to the “vain imaginations” that we worship.
If this appraisal is correct, then the message of the angel to Nephi is that our successfully going to the tree of life may be as simple as having a correct perception of reality, and going anywhere else is only pretending that a non-reality has worth, and then seeking after that pretended worth. Then of course, when we get it, pride is making sure everyone else recognizes that we have it.