Matthew 24:23

Then if any man shall say unto you, Lo, here is Christ, or, Here; believe it not. For there shall arise false Christs, and false prophets, and shall show great signs and wonders; so as to lead astray, if possible, even the elect. Behold, I have told you beforehand. If therefore they shall say unto you, Behold, he is in the wilderness; go not forth: Behold, he is in the inner chambers; believe it not.

Although the disciples saw Christ ascend, the very fact that they expected him to return made them vulnerable to the claims of false Christs, pretending to be the Messiah. Christ warned that his second coming would be worldwide, glorious, sudden, and open for all the world to behold, thus contrasting sharply with the secretive pretensions of false Christs in secret chambers, remote wildernesses, or deserts. That many such pretenders did arise prior to the destruction of Jerusalem is fully attested. H. Leo Boles said:

Many persons, impostors, and self-deceived, aspire to fill the places of persons of honor. Many did come claiming to be the Christ. There is still a constant stream of men claiming to be God's chosen servants, leading multitudes into sin and infidelity with pretended claims.[10]

The mark of secrecy, as of something hidden, known only to the "insiders," was an unfailing characteristic of false Christs and false teachers; but not even the first advent of Christ was distinguished by any such concealment. Those marvelous things of the true Christ "were not done in a corner" (Acts 26:26). The very heavens burst into praise the night he was born. His great wonders were performed before vast multitudes, and his credentials as the true King were presented repeatedly before the highest tribunals of the people, both Jews and Gentiles.