As we discussed earlier, one of the characteristics of God’s will is that God calls us to do the impossible! But to face the impossible requires faith. Satan knows that if he can inject unbelief into our spirits, he can effectively rob us of God’s best for our lives. For this reason unbelief is a deadly enemy of God’s plan for your life.

I think many of God’s people don’t realise how sinister and dangerous unbelief is. Many pious and self-righteous Christians look down their religious noses at people committing other, more visible sins. They criticise them sharply without realising that the unbelief they harbour in their hearts, and in some cases enshrine in their doctrines, is more wicked in God’s sight than the sins they are condemning.

Jesus rebuked His disciples for unbelief more than any other thing. The reason unbelief is so dangerous is that not only is it a sin in itself, but it also can be a gateway for other sins as well.

There have been many wonderful books written and many powerful sermons preached about faith. Indeed, faith is the currency of God’s kingdom, and without faith it is impossible to please God (Heb. 11:6). However, I think many people have a basic misunderstanding about faith. They pray and seek more and more faith. But what if I told you that you already have plenty of faith? The problem is not that you have too little faith; the problem is something else. What if I told you that your faith is already enough to move mountains? Many people will find this hard to accept, but it is very biblical.

In Mark 9:24 a man said to Jesus, “I do believe; help me overcome my unbelief!” (NIV). Notice that he didn’t ask Jesus to give him more faith. In fact, he said, “I do believe.” This man recognised that the problem was not too little faith but too much unbelief! Perhaps you don’t see the distinction I am making here. Some people think unbelief simply means “no faith.” But it is possible to be an unbelieving believer. In other words, faith and unbelief could be present at the same time. Faith has the potential to move mountains, but unbelief will nullify the power of faith. Let me explain it like this.

When my wife was still in Bible college, her father bought her a very special gift: a car! It was a brand-new, silver diesel Volkswagen Jetta. It was a wonderful car that served us well for a long time. One day she lent the car to a friend. On his way to return the car to us, as a courtesy he decided to refill the fuel he had used. He pulled into the gas station, inserted his credit card, opened the cap of the gas tank, and began to fill it—with gasoline! How he missed the bold red warning on the tank that said to use “DIESEL FUEL ONLY” I will never know. But one thing is certain; his little mistake was costly for us and devastating for the vehicle.

After the gasoline was added, the vehicle would no longer run. It’s not that there was too little diesel in the tank. The problem was the injection of a substance that was incompatible with the vehicle’s design. This is exactly how unbelief works. The devil wants to inject unbelief into our spirits because he knows it will bring us to a screeching halt.

In Matthew 17:20 Jesus said, “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.” The mustard seed is the smallest of all seeds. Some would conclude that if faith as a grain of mustard seed can move mountains, then they must not have any faith at all, because so far they have been unable to move even a thimble. However, Romans 12:3 says God has given everyone a measure of faith.