There is an unbelief that comes from a heart being hardened toward God. For example, let’s say someone had a bad experience with Pentecostals. At one time, they were exposed to preaching about the baptism of the Holy Spirit, speaking in tongues, miracles, etc. But then they saw some Pentecostal do something really wild, something irresponsible, something that offended them and they rejected it.
So they hardened themselves and said, “I hate that. I don’t want anything to do with it.” They turned away from tongues and gifts of the Spirit altogether. Now they’re in a state of unbelief, but it’s an unbelief by choice. They hardened themselves, so it’s actually a rebellious kind of unbelief. It can eventually wreck a person’s life.
But say another person is seeking God with their whole heart, believes in the baptism of the Holy Ghost, and desires it. It’s not that they’re rebellious; they long for it, but they can’t seem to get it. Some people have been tarrying for the Holy Ghost for thirty years! That can come through wrong doctrine. Or it can come because a person never gets beyond the realm of feelings. They’re hung up on their feelings, waiting for an experience. And because they haven’t felt or seen anything, they can’t believe.
Their physical senses have become so dominant over them, they can’t get beyond that. They can’t believe for anything they can’t see, taste, hear, smell, or feel. That’s what I call a natural type of unbelief. Everybody has it. Nobody naturally believes God. You have to exercise your senses to believe God. It’s like a muscle. You have muscles in your body, but none of them are naturally huge and bulging. If you leave them alone and do nothing, they’ll atrophy. They don’t naturally grow, they decay.
In the same way, your senses will dominate you if you don’t make a deliberate effort to exercise them.
This natural type of unbelief is what the Lord is talking about in Matthew 17. The disciples believed that God could do miracles — they had cast out demons themselves. But in this case, they weren’t able to see deliverance. I believe the reason the disciples had unbelief was because the epileptic boy fell on the ground, wallowed, and foamed at the mouth (Luke 9:42). If you’ve ever seen an epileptic attack right in front of you, it will send goose bumps up and down your spine. Fear will assault you.