24 And truth is knowledge of things as they are, and as they were, and as they are to come; (D&C 93:24)
The Spirit manifests the truth.
13 Behold, my brethren, he that prophesieth, let him prophesy to the understanding of men; for the Spirit speaketh the truth and lieth not. Wherefore, it speaketh of things as they really are, and of things as they really will be... (Jacob 4:13)
The truth, when lived, imbues the individual with light and glory.
34 And again, verily I say unto you, that which is governed by law is also preserved by law and perfected and sanctified by the same. (D&C 88:34)
Those who do not live the truth possess a lesser degree of glory.
21 And they who are not sanctified through the law which I have given unto you, even the law of Christ, must inherit another kingdom, even that of a terrestrial kingdom, or that of a telestial kingdom. (D&C 88:21)
Each kingdom has a both a degree of glory and a law, or degree of truth, associated with it.
36 All kingdoms have a law given;
37 And there are many kingdoms; for there is no space in the which there is no kingdom; and there is no kingdom in which there is no space, either a greater or a lesser kingdom.
38 And unto every kingdom is given a law; and unto every law there are certain bounds also and conditions. D&C 88:36-38
What is the law, or degree of truth, associated with the Telestial kingdom, or the world in which we now live? It is to lie.
103 These are they who are liars, and sorcerers, and adulterers, and whoremongers, and whosoever loves and makes a lie. (D&C 76:103)
The Telestial kingdom is a kingdom of lies. The Telestial kingdom is the opposite of truth--it is the opposite of things as they really are. It is things as they are not.
This world is populated by two kinds of people. The first kind, who make up the vast majority, are lightless souls who love and make lies. The second kind, which are the minority, are those who have condescended to dwell here for the benefit of the first through abdicating the right they had previously earned to live in a greater kingdom.
A simple but effective heuristic for success in this world--where most inhabitants love and make lies--is to look at what everyone is doing, and do the opposite. The gospel is called the strait and narrow because so few find it. It is always the minority of the minority who seek after, implement, and love truth. It is never a popular trajectory.
I felt impressed to make a brief high-level summary of the lies that we live by in a few areas. This sort of thing could be done for every category on this earth.
Spirit: Most people spend their lives in the hamster wheel of church life. They are ever learning, but never come to the knowledge of the truth (2 Tim. 3:7), or the revelation of Jesus (Gal. 1:2), otherwise known as God revealing himself to an individual (John 14:18), otherwise known as eternal life (John 17:3). They spend all their spiritual capacity on means that can never bring them to God. Despite having more discretionary time than any other generation in the history of the world, they are as far from God as any generation in history, despite thinking they are making great progress. The best thing they can do is operate under the assumption that everything they think they know about religion is actually wrong, and seek God with the meekness and teachability of a child to retrain themselves in the way, the truth, and the life. Our religious behavior is a lie.
Marriage: Most people spend their lives in the hamster wheel of finding a spouse who fulfills them. Their expectations of what marriage is supposed to be are complete rubbish. The spouse who meets their expectations does not exist, and the marriage they seek would not fulfill God's purpose in marriage. So, they spend their lives either ever seeking and never finding a spouse, or divorcing spouse after spouse, or cheating on their spouse, or being generally miserable with their spouse, because their perception of marriage is nothing but a lie.
Food: Most Americans are overweight. We Americans live in a time of unparalleled availability of food, and while we eat more than any generation in the history of the earth, we are actually malnourished. Why? First, we don't eat based on what we need to function (what feels good in the long run), we eat based on what feels good now. As a result, nutrition is an afterthought. Second, even when we eat things that look healthy, we are usually eating factory-farmed food that has been grown on depleted soil. Through these and other factors, while we have more food than ever before, it is less nutritious than ever before. Our food is a lie.
I recently began practicing a farming ideology that creates an optimal nutritional environment for the plants I create. Instead of doing things as others do them, I am doing things to maximize the nutrition and yield of my garden. What would happen if we did this sort of thing in every aspect of our lives? Everything, from the food we eat to how we work to how we handle our marriages to how we live our religion, and everything else. What if we lived, ate, and slept by truth?
The devil tempts us through carnal senses. What we hear, what we see, what we smell, what we taste, and what we feel. These are the categories where we are flooded with lies. None of these senses should be trusted. We should not choose the food we eat based on what it tastes like. We should not choose our spouse by the way they make us feel, and so on. Ideally, we would judge based on truth, and not the carnal senses:
And shall make him of quick understanding in the fear of the Lord: and he shall not judge after the sight of his eyes, neither reprove after the hearing of his ears: (Isaiah 3:11)
24 Judge not according to the appearance, but judge righteous judgment.The devil's greatest power is that of expectation. When our minds are full of lies, he has power over us through our expectations. (John 7:24)
We waste our lives in the counterfeit pursuit of things that cannot bring us the deep satisfaction that can only be won in toiling pursuit of the truth. We are fully occupied and divert our time, energy, and talents to that which is of no worth.
51 Wherefore, do not spend money for that which is of no worth, nor your labor for that which cannot satisfy. Hearken diligently unto me, and remember the words which I have spoken; and come unto the Holy One of Israel, and feast upon that which perisheth not, neither can be corrupted, and let your soul delight in fatness. (2 Nephi 9:51)
In the end, we deprive ourselves of what we need for spiritual, physical, and other sustenance, and end up malnourished in every sense.
39 O, my beloved brethren, remember the awfulness in transgressing against that Holy God, and also the awfulness of yielding to the enticings of that cunning one. Remember, to be carnally-minded is death, and to be spiritually-minded is life eternal. (2 Nephi 9:39)