In Matthew 17, we have an instance where the Lord’s disciples tried to ‘rebuke the devil’ that he come out of a man’s son. They failed. We read in Matthew 17:19-21, “Then came the disciples to Jesus apart, and said, Why could not we cast him out? And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you. Howbeit this kind goeth not out but by prayer and fasting.” We see that even true believers had trouble casting out demons.

Let’s consider Mark 3:14-15, “And he ordained twelve, that they should be with him, and that he might send them forth to preach, And to have power to heal sicknesses, and to cast out devils.” The Lord empowered all twelve of His disciples so that they might cast out devils. Judas was among the twelve and we know that he was not a true believer, for we read in John 6:70-71, “Jesus answered them, Have not I chosen you twelve, and ONE OF YOU IS A DEVIL? He spake of Judas Iscariot the son of Simon: for he it was that should betray him, being one of the twelve.” There is no indication in scripture that Judas did not drive out demons along with the other eleven apostles.

Now, let’s look to a future day when men will appear before the Lord. We read in Matthew 7:21-23, “Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not PROPHESIED IN THY NAME? and IN THY NAME HAVE CAST OUT DEVILS? and in thy name done many wonderful works? And then will I profess unto them, I NEVER KNEW YOU: depart from me, ye that work iniquity.” Here we see unbelievers claiming to have prophesied and cast out demons in the Lord’s name. These men were never saved for the Lord said that He NEVER knew them.

What do we make of this? Can unbelievers really prophesy and cast out demons successfully by using the name of the Lord? I believe we have at least two scenarios that can possibly answer your question.

*Satan is a formidable foe. He could very easily command his demons to obey the words of one not saved if it fit his evil plans. If one could exhibit power over demons, and with that power, he could draw men to follow him, that would play right into Satan’s hands. With that satanic fueled power, men could easily draw others away from Christ and from the truth of the scriptures.

* There are many charlatans today who put on a show of prophesying and driving out demons. We see many of these men and women on TV today, exhibiting power to prophesy and heal diseases. Very often they make prophesies that do not come true, yet people still follow after them. A false prophet in the Old Testament was dealt with seriously. We read in Deuteronomy 18:20-22, “But the prophet, which shall presume to speak a word in my name, which I have not commanded him to speak, or that shall speak in the name of other gods, even THAT PROPHET SHALL DIE. And if thou say in thine heart, How shall we know the word which the LORD hath not spoken? When a prophet speaketh in the name of the LORD, if the thing follow not, nor come to pass, that is the thing which the LORD hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him.” So, even one missed prophesy showed that he was not a prophet of God.

To answer your question, I would say that NO, an unbeliever cannot truly use the name of Christ to command demons or to prophesy. However, Satan could be behind their words and deeds to try to accomplish his purposes, or one could be a fraud and try to imitate those powers for their own gains (mostly financial gains).

I will close with a strong caution from the scriptures. 1 John 4:1-3 says, “Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world. Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God: And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.” (336.6)