However, when Jesus spoke of the end-times, he warned about signs and miracles associated with final leaders (Mk. 13, Lk. 21, Mt. 24). He said that even the elect might be tempted to believe them. There are several reasons to be alert concerning signs.
One Shinchonji instructor explained that the biggest sign in SCJ is being able to interpret Revelation. Another Shinchonji member mentioned that Manhee Lee miraculously recovered from being thrown into a river. Another member said that Mr. Lee is the only one who has witnessed the events in Revelation. Other Shinchonji members formulate a list of Revelation signs/questions that no Christian can answer.
When a sign removes a spiritual truth in the written word, Christians discern the sign is not from God. A spirit of prophecy is not going to change what God's voice in the written word was making clear to the Christian world. For example, Mohammad's revelation states that Jesus Christ did not die on the cross, but this goes against the clear message in the record of the New Testament.
Likewise, Manhee Lee's sign of Revelation explanations should not remove what God's voice in the written word was already making clear. Even though final prophets say that they have the power to give new meanings (through revealed knowledge of opened seals), the voice in the written word is still superior. Many of the understandable ideas in Revelation and other parts of the New Testament record are changed/re-defined because of Mr. Lee's sign.
Second, another reason to be careful about signs is that they distract people from the real spiritual life God wants us to live. Instead of focusing on the simple and important truths from the Lord (i.e. reaching out to others, growing in love, serving Christ with the gifts he has given us, explaining Jesus' remedy and love to others, etc.), people end up focusing too much on revelation knowledge in end-time movements.
Lastly, a sign also blinds people from accepting problems in their movement. They minimize errors by pointing to positive signs in their group. While talking to a woman in Shinchonji, she dismissed many problems by repeating that Manhee Lee was an eyewitness of the events in Revelation. She did not see how this is spiritually inconsistent.