The Big Lie on Wikipedia is the idea that the more blatantly false an idea is, the more likely people will believe it. Interesting that The Big Lie is seen differently from different perspectives. Even biblically, Satan says the Big Lie is that God is good. God says the Big Lie is believing there is no God, or that he is inconsequential. And, to different degrees, everyone falls into one or the other camp. All in all, it's about one's perspective of reality or worldview.
Most people believe that real life is having a solid earthly perspective. They relegate spiritual life to a set of esoteric beliefs that may help us psychologically, but isn't as important as an earthly perspective. That's the Big Lie. Even a religious person who puts more stock in acting spiritual, does so for earthly gain (monetary or public praise). In fact, everyone who ignores a biblical mindset in lieu of appearing spiritual for earthly reasons is of the Big Lie.
The believer, on the other hand, sees all of reality through the lens of a biblical mindset. Their minds are on heavenly gain, and on an heavenly agenda. Earthly life is seen as important, but only in a subordinate role to heavenly realities. They aren't radicals who ignore a biblical perspective, but they are radical in the sense that they are not like most people, who do not know the Spirit. (2 Thessalonians 2:11-12; Philippians 3:18-21; Colossians 3:1-4)