"Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world." 1 John 4:1
Satan and his fallen angels are lying spirits who speak into our consciousness. The front line of the battle with the demonic forces of darkness is the threshold of our minds.
These spirits have no real power to force you to do anything, but are experts at tempting you where they find a weakness. When Jesus told His disciples that He must be handed over to godless men to suffer and die, Peter quickly stepped in and said, -"Never!" for which he received a strong rebuke, -"Get behind me Satan!"
Now, Jesus knew that it was really the devil speaking though it was Peter standing before Him. Peter reacted emotionally and failed to test the spirit which moved him to try to prevent Jesus from giving His life. After all, Jesus said that it was the very reason for which He had come into the world. Without His sacrifice, all mankind would perish in the Lake of Fire.
On another occasion, two of Jesusí disciples asked His permission to call fire down from heaven to destroy some men who were arguing with them, to which Jesus replied, -"You do not know from what spirit you speak." Again, it was spirits presenting alien thoughts and moving them to speak unwisely. This is why the Bible tells us to be quick to hear and slow to speak.
Lying spirits can also give us visions and dreams. We test the spirits by bringing whatever they say or show us to the Word of God. Lying spirits will often claim that they come from God, or that it is the Holy Spirit speaking.
All prophecies, any word of knowledge, vision or dream must be confirmed by the Bible, which is the written Word of God. Even Jesus, who had existed from all eternity as God, used the written Word to answer the devil when he was being tempted. Repeatedly, Jesus replied, "It is written."We must always be diligent to test the spirits and also to remain humble, because without humility a person can want the message to be from God so badly that they fail to test it.
The Apostle Paul told the Church to capture every thought and bring it to the obedience of Christ. We canít control what thoughts may come into our minds, but we can control what we allow to stay what we accept and believe. I love how Corrie Ten Boom put it, -"You canít stop the birds from circling over your head; but you can prevent them from making a nest."