You do not need to be a professional theologian to combat cessationism and other doctrines of demons. If you have knowledge, use your knowledge. If you can argue, then argue. For those of us who are called to ministry as a vocation, it is especially important to follow the footsteps of Christ in preaching and healing. We announce the truth to the masses, and the Spirit of God will change the hearts of those called to believe the word of God. As for the demonstration of the gospel, there are supernatural things that we can do other than healing, but I recommend placing an emphasis on it. The reason is that the ministry of healing not only shows forth the teaching of the gospel, but it also displays the kindness of God, and it removes suffering and saves lives.
Compassion is our motivation. We already believe the truth, and we have faith to receive for ourselves, so we are going to be fine no matter what other people believe. We teach people the word of God for their benefit. We do not need them to believe before we can receive. If they refuse to believe, it will only hurt them. Our motivation is not to vindicate ourselves. Relative to my own life, I do not care what other people believe, since I have all that I need. I do not need to prove anything to them. I do not need to care about whether they believe in healing. They are the ones staying sick, not me. But I tell them the truth anyway. And we do that because God has commissioned us, and he has place his love in our hearts, so that we wish to save the people from their sin and suffering. Surely we ought to fight unbelief, and when it comes to demonstration, there are other kinds of miracles besides healing the sick, but begin with ministries of compassion, and then we will both uphold the gospel and save the people.
Any Christian can declare and demonstrate the gospel. Even those who have not attained enough knowledge, and even those who have not learned to heal the sick and work other miracles, can still do their part to advance the doctrines of faith. Now if you have never healed the sick in the name of Jesus, there is no need to wait. When an opportunity arises, simply obey the word of God. Do not shortchange yourself. But for now I wish to bring up something even more basic, and that is to let the Bible do its own work. If you have the Bible, then there is always something you can do. No matter how untrained you are, and no matter how timid you are, there is something you can do. If you think you are too inarticulate to preach, and if you think you are too weak in faith to heal the sick and cast out demons — these are excuses — or if somehow you lack the opportunity, if you have the Bible, you can do something.
Let the Bible do its work by making people read it. If for whatever reason you can do nothing else, you can always do this. Make them read about the God of signs and wonders. Make them read about Jesus’ promises and commands that ensure the increase of miracles by all his followers, all those who have faith in him. Make them read about the teachings and examples of those who in the early days obeyed the Lord and achieved results, receiving visions and prophecies, healing the sick, casting out demons, and even raising the dead. If for some reason you cannot teach the Bible, or if you cannot carry on a debate about it, and if for some reason you have no opportunity to demonstrate by healing the sick or performing other signs and wonders, then make the people read the Bible. Just read it.
Here is what you can expect from this. Consider the parable of the sower. The seed is the word of God. Some people hear the word of God but fail to grasp it, and so the devil comes and steals it from their hearts. Some appear to receive the word of God with joy, but they only believe until they run into circumstances that trouble them. Then some hear the word of God, but they are taken up with the life of the world, and the truth does not bear fruit in their lives. Accept the fact that not every person will believe, and among those who claim to believe, not every person will produce results. However, the good news is that there are some people who will hear the word of God and understand it, and they will put the word of God into action, producing a hundred, sixty, or thirty times what was sown into their hearts. This is what you can expect when you make people read what the Bible says about miraculous powers and experiences.
We have seen someone who has a nagging doubt. What happens there? A recurring thought persists in his mind and harasses him. The thought has been planted in his mind, and because it has not been eradicated, it grows and begins to choke out other thoughts. But the reverse can also happen. The word of God is able to produce nagging faith in a person. He thinks that his unbelief is correct, but the Bible teaches something different. If this is planted in his heart and not uprooted, it will increase and compete against his unbelief. As it is written, “God gives the increase.” He is able to overturn a person’s stronghold of unbelief, starting with a seed.
Make people read the Bible. Literacy is devastating for cessationism and other forms of unbelief. The cessationist can say anything he wants, and some people will believe him, but as long as people can read for themselves, they will see that the Bible says something different. They will see that the cessationist is a teacher of unbelief, a messenger of Satan who introduces a non-Christian religion to the people. They will see that their preachers and theologians have lied to them. Their false doctrines function to divert attention from their own failure and wickedness. Make them read the Bible. As long as people can read, cessationism can never win.