A evil spirit that comes to us does not announce, "I am from the Devil and I have come to lie to you and make you believe that lie." That would be ridiculous! Most of us would immediately turn that spirit off and command that it leave. The enemy is more deceptive than that. He often comes to us disguised as a messenger from God. He may also come to us in the first person, "I" to make us think that we are talking to ourselves. He may say, "I am depressed." Then we may say in our minds, "Yes, I guess I am really depressed." When we are thinking we are having a monologue, we may be actually having a dialogue with the enemy.
How do we test the spirits? I John 4:2-3 gives one test. It says that every spirit that does not confess that Jesus is the Anointed One who came in the flesh is not of God. We can also demand that the spirit declares that Jesus is Lord (I Corinthians 12:3). Another practical application of discernment is to reword the statement of the spirit and add "in the name of Jesus." Using the above example we would say, "I am depressed in the name of Jesus." That sounds rather insane. We have blown the enemy's cover! One of the best ways to discern the nature of a spirit is to check the Word of God. Does what the spirit says match up with the Word of God?
The Word says that the weapons of our warfare are not carnal, but mighty through God to the pulling down of strongholds. We are to cast down imaginations, and every high thing that exalts itself against the knowledge of God and bring into captivity every thought to the obedience of Christ (II Corinthians 10:4-5). I have in my file about a page and one half of lies that the enemy has used on people to make them become suicidal in their thinking. We must answer each lie with the truth of the Word of God.
Now looking at the spirit that came to the friend of Job, we find  the spirit appealed to his desire for special revelation (verse 12). This is what the serpent did with Eve in the Garden when he said, "You will become as gods, knowing good and evil."  The spirit came in the night, evidently the form of a nightmare (verse 13).  The approach of the spirit was intimidation (verses 14-15). Fear is not God's approach to Believers. God does not give us a spirit of fear, but of power, love, and a sound mind. Whenever people were fearful of angels, the angels said, "Fear not."  There is an obscurity of the form (verse 16). We do not find obscurity in the appearance of angels in Scripture.  The message begins with an accusation. Who is the accuser, but Satan?
 Does God trust His servants (verse 18)? God often intrusted his Word to His angels. Why was this spirit so sensitive about God charging some of His angels with folly? This was one of the angels that rebelled with Satan. It is no wonder that this evil spirit was bitter and carried a grudge against God.  Does God trust man with anything (verse 19)? Yes! He has trusted His Church to carry His precious Gospel into all the world.  Is man destroyed without God caring about him (verse 20)? Look at the hopeless implications. God, however, keeps record of the sparrows that falls and the deaths of His saints are precious in His sight.  Is life upon this earth futile and without purpose as this spirit would have us believe (verse 21)? The obvious answer is, "No!" We have a purpose to serve the Lord. Furthermore, God works all things together for our good.
As a Christian and also as a Christian Counselor,
I find it essential to have discernment of spirits. We are not to be ignorant
of the devices of the enemy. Therefore, I pray this exercise in discernment