Why should believers not go out to look for the Messiah in the desert or secret chambers?
Believers should not go out because false Christs and false prophets will arise and show great signs and wonders, empowered by Satan, to deceive even the elect if possible. Any claim that the Messiah is in the desert or secret chambers is false; He will come from heaven in power and glory.
Les explains that when things get tough, people turn religious, so Jesus warns about false Christs and false prophets who show great signs and wonders. Their power does not come from God but from the devil, from Satan, and they could deceive the very elect if possible. Jesus repeats for emphasis that if anyone says the Messiah is in the desert, believers should not go out, and if He is said to be in secret chambers, they should not believe it. The Messiah is not coming from those areas. He is coming from heaven, and when the tribulation has ended, it will be time for the Second Coming, when He comes in power and glory and destroys the nations gathered in the Middle East under the Antichrist.