And the disciples of John reported to him about all these things. Summoning two of his disciples, John sent them to the Lord, saying, “Are You the One who is to come, or should we look for someone else?”

When the men came to Him, they said, “John the Baptist has sent us to You, saying, ‘Are You the One who is to come, or should we look for someone else?’”

At that very time He cured many people of diseases and afflictions and evil spirits, and He granted sight to many who were blind.

And He answered and said to them, “Go and report to John what you have seen and heard: the blind receive sight, the lame walk, the lepers are cleansed, and the deaf hear, the dead are raised up, the poor have the gospel preached to them. Blessed is he who does not take offense at Me.” (Luke 7:18-23)

Mark tells of the father of a demon-possessed son who famously said, “I do believe; help my unbelief” (Mark 9:24).

What a strange statement. But we all understand that. We understand believing doubt, or doubting belief. And that father’s testimony is the testimony of most of us. I do believe; help my unbelief.

That is to say, “I believe, but my faith is incomplete. My faith is assaulted and fraught with doubts.”

Astonishingly, that is exactly the situation in Luke 7 — not with just a passing stranger such as the father, but with the greatest man who had ever lived up until his time, John the Baptist (Matthew 11:11). Here is a prophet of God, the forerunner of the Messiah, the last of the Old Testament prophets and the greatest, who is struggling with doubt.

If you had been there during the events of the life of Jesus, you would have plenty of reason to believe in Jesus as the Messiah. If you had any association with the family of Jesus, or with the family of John the Baptist, you would know of the affirming evidences that Jesus was the Messiah.

If you were hanging around the apostles, you would have ample evidence to believe that Jesus is God in human flesh. And even reading the New Testament, the proof is replete. There is the testimony of angels — the angel who came to Zacharias while he was doing his priestly duty in Jerusalem, the testimony of the angel Gabriel who came to Joseph and Mary, and the testimony of the angels who spoke in vast numbers to the shepherds in the fields.

They were well aware of the fact that Jesus came down through the Davidic messianic line. They were all aware that John the Baptist himself had given testimony that this is the Lamb of God who takes away the sin of the world. They were aware that when John baptized Jesus, the Spirit of God came down, descending upon Him in divine affirmation.

And there was no other explanation for the teaching of Jesus, His power over disease, demons, and death, except that He was God exercising divine power. There was plenty of evidence — plenty of reason to believe that Jesus was the Messiah. But here, we find doubt on the part of John the Baptist, the greatest man who ever lived.

Doubt is very real for people who believe. It is a reality, but it is not an acceptable reality, and it needs to be addressed. Moses doubted God. Gideon doubted God. Elijah doubted God. Jeremiah even expressed doubt. The apostles doubted, and here John the Baptist doubts.

We understand that. Coming face-to-face with doubt is coming face-to-face with ourselves. And that’s why this is an important passage, because it’s going to help us to be able to deal with doubt.

Now, what do we mean by doubt? Let me give you a simple definition: Doubt is a struggle to believe. It is something that prevents me from fully believing. It can be momentary. It can be prolonged. It can be permanent.

But I want you to understand how the Gospels deal with doubt. Whenever Matthew, Mark, Luke, and John deal with a doubting person, it’s always a believer. There is one occasion in John 10:24 where it says the Jews were saying to Jesus, “How long will You keep us in suspense? If You are the Christ, tell us openly.” But that wasn’t honest doubt. That wasn’t a struggling to believe. That was just their unbelief trying to put Jesus on the spot. Every true expression of doubt in the four gospels relates to believers.

Doubt is something that is part of being a believer. So we again go back to what the man said: “Lord, I believe; help my unbelief.” You can identify with that, and so can I. There have been times in all of our lives when, in the midst of our believing, we struggled with doubts.

Doubt is presented as a believer’s problem. So we shouldn’t be surprised to find John the Baptist, a godly prophet, struggling with doubt. If the greatest man who ever lived had some doubts, then maybe it’s understandable that we have some doubts as well.

This post is based on a sermon Dr. MacArthur preached in 2001, titled “Why the Believer Doubts, Part 1.” In addition to serving as the pastor of Grace Community Church and the voice of Grace to You, Dr. MacArthur is the chancellor of The Master’s University in Santa Clarita, Calif. You can learn more about TMU at masters.edu.