After the believer’s mind is controlled by evil spirits, his thoughts become entirely undependable because he is responsible for very few of his own thoughts. Most of the thoughts are generated by evil spirits in his mind. It is very easy at such a moment for evil spirits to give the believer one kind of thought at one time and give him a completely opposite kind of thought at another time. Because the believer follows these kinds of thoughts, he becomes a vacillating person. People who work with him or who are together with him consider these instant changes as a characteristic of his unstable character. Actually, it is evil spirits who are changing the thoughts in his mind and altering his judgments. We often see a believer saying, "I can," at one moment, and "I cannot," at another moment. In the morning he says, "I want it," but in the afternoon, he changes and says, "I do not want it." This happens because evil spirits will inject the thought of "I can" into the believer’s mind at one moment. Then the believer will think that he can really do it. At the next moment, however, evil spirits will inject the thought of "I cannot" into his mind. Then he will begin to think that he cannot do it, and he will change what he said at the beginning. In many conversations, when the tone suddenly changes, we can detect the work of evil spirits in the minds of men. The believer himself may hate such a vacillating life, but he is not his own person and has no way to stabilize himself. At the same time, if he does not act according to the injected thought, evil spirits will imitate the voice of his conscience and accuse him of not acting according to God’s leading. Since he wants to avoid this kind of accusation, he has no choice but to fluctuate back and forth before men. Many fluctuating works have this source as their origin. When a believer listens to the suggestions of evil spirits in his mind, he ends up with many sudden works; when evil spirits change the subject, the believer’s work changes with it. Evil spirits always make people think at the wrong time. They will wake up the believer in the middle of the night and tell him what he should do. If the believer does not do it, they will accuse him. Or they will tell the believer to change his way in the middle of the night and cause the believer to make very important decisions at a time when the mind is most confused. If we investigate the source of these matters, we will see that many sudden changes in events are the result of the work of evil spirits in the minds of men.
Believers who have evil spirits working in their minds sometimes do not like to talk with people because they have no strength to listen to people. The tides of thought in their minds are like rising winds and surging clouds that cannot be stopped by the words of others. However, they can at the same time be very talkative. Since theirs minds are filled with "thoughts," their mouths cannot help being filled with words. A mind that cannot listen to others, which only wants others to listen to it, is very often a sick mind. Many believers seem to be talkative and gossipy by nature. Actually, they are probably just a machine of evil spirits. Many believers seem to be a kind of "talking machine" of evil spirits!
When many believers are chatting, joking, and slandering behind the backs of others, it seems as if they cannot control their own tongues. They are very clear in their hearts that they do not know what they are talking about. Even when they know what they are talking about, they often do not know how to stop or restrict their unprofitable words. It is as if an idea comes into their minds, and it cannot wait for even the slightest consideration before it comes out as words in their mouths. The tides of thoughts roll in and cause believers to speak many things involuntarily. Their tongues are no longer under the control of the mind and will. Many words that the mind has not thought through and that the will has not decided to say, nevertheless, are spoken. Sometimes words that are completely contrary to a person’s motive and will are uttered. Only when such a person is reminded of his actions does he wonder why he spoke those words. This all occurs because the mind is passive. Evil spirits can utilize man’s tongue through the passive mind. In the beginning, evil spirits just mix their thoughts with man’s mind. Later, they mix themselves in with man’s words also. When that happens, his mind will no longer be able to understand the thoughts of others or remember anything.
A believer should insure that his words have passed through his own mind first. All the words that have not passed through the thinking process are from evil spirits.
(Spiritual Man, The (3 volume set), Chapter 32, by Watchman Nee)