This statement, found in Mark 9:24, has been a source of many questions. What did the father of a demon possessed son mean when he spoke to Jesus? Although Matthew records the same event, Mark records a more detailed periscope of a demon possessed boy who the disciples are unable to cure.

When they came back to the disciples, they saw a large crowd around them, and some scribes arguing with them. Immediately, when the entire crowd saw Him, they were amazed and began running up to greet Him. And He asked them, "What are you discussing with them?" And one of the crowd answered Him, "Teacher, I brought You my son, possessed with a spirit which makes him mute; and whenever it seizes him, it slams him to the ground and he foams at the mouth, and grinds his teeth and stiffens out. I told Your disciples to cast it out, and they could not do it." And He answered them and said, "O unbelieving generation, how long shall I be with you? How long shall I put up with you? Bring him to Me!" They brought the boy to Him. When he saw Him, immediately the spirit threw him into a convulsion, and falling to the ground, he began rolling around and foaming at the mouth. And He asked his father, "How long has this been happening to him?" And he said, "From childhood. It has often thrown him both into the fire and into the water to destroy him. But if You can do anything, take pity on us and help us!" And Jesus said to him, "'If You can?' All things are possible to him who believes." Immediately the boy's father cried out and said, "I do believe; help my unbelief." (Mark 9:14-24)

When they came to the crowd, a man came up to Jesus, falling on his knees before Him and saying, "Lord, have mercy on my son, for he is a lunatic and is very ill; for he often falls into the fire and often into the water. I brought him to Your disciples, and they could not cure him." And Jesus answered and said, "You unbelieving and perverted generation, how long shall I be with you? How long shall I put up with you? Bring him here to Me." And Jesus rebuked him, and the demon came out of him, and the boy was cured at once. Then the disciples came to Jesus privately and said, "Why could we not drive it out?" And He said to them, "Because of the littleness of your faith; for truly I say to you, if you have faith the size of a mustard seed, you will say to this mountain, 'Move from here to there,' and it will move; and nothing will be impossible to you. But this kind does not go out except by prayer and fasting." (Matt 17:14-21)

The background of this periscope was established earlier when Jesus commissioned the twelve disciples and gave them "authority over unclean spirits" (Mark 6:7-13). Now, in failing to exorcise the young boy, their credibility is at risk in failing to demonstrate the power of God, and this may have been the basis of the scribes' public argument with the disciples.

When Jesus learns of the disciples' failure, He addresses everyone as an "unbelieving (apistos) and perverted generation." The Greek adjective "apistos" describes one who is actively disbelieving and is viewed as unfaithful / unbelieving. With this attitude, the unbeliever himself does not earn the confidence and trust of another.

When the father implores Jesus, "But if You can do anything, take pity on us and help us!" (Mark 9:22b), Jesus counters the doubt in the plea, "'If You can?' All things are possible for the one who believes." (Mark 9:23)

The periscope is revealing about Jesus and the faith that He is teaching. Jesus did not come as a divine healer but a divine healer in God's name; Jesus always made clear that the source of power comes from God.

"I can do nothing on My own. As I hear, I judge; and My judgment is righteous, because I do not seek My own will but the will of Him who sent Me. (John 5:30)

Philip said to Him, "Lord, show us the Father, and it is enough for us." Jesus said to him, "Have I been with you for so long a time, and yet you have not come to know Me, Philip? The one who has seen Me has seen the Father; how can you say, 'Show us the Father'? Do you not believe that I am in the Father, and the Father is in Me? The words that I say to you I do not speak on My own, but the Father, as He remains in Me, does His works. Believe Me that I am in the Father and the Father is in Me; otherwise believe because of the works themselves. (John 14:8-11)

The failure of the disciples may have been result of forgetting this important fact.

The distinctive feature of Jesus' teaching about faith is that God's power is unlimited; the Believer's faith is boundless. God's / Jesus' promise rests upon God's word of power and a Believer's supplication. It requires a special kind of faith – the kind of faith that Jesus has in His Father.

And Jesus answered and said to them, "Have faith in God. Truly I say to you, whoever says to this mountain, 'Be taken up and thrown into the sea,' and does not doubt in his heart, but believes that what he says is going to happen, it will be granted to him. (Mark 11:22-23)

Be on your guard! If your brother sins, rebuke him; and if he repents, forgive him. And if he sins against you seven times a day, and returns to you seven times, saying, 'I repent,' you shall forgive him." The apostles said to the Lord, "Increase our faith!" But the Lord said, "If you had faith the size of a mustard seed, you could say to this mulberry tree, 'Be uprooted and be planted in the sea'; and it would obey you. (Luke 17:3-6)

The periscope is revealing about ourselves and our understanding of faith.

A Believer's unbelief is not the rejection of Jesus Christ as the Messiah and Son of God; instead, it is in doubting His word and whether He would do what He said He would do. The Believer's unbelief / doubt is seen as Believers "of little faith" and "of hardness of heart." It appears that faith is a belief in the reality of Jesus Christ Messiah and measured by the trust a Believer places in His words.

Immediately Jesus stretched out His hand and took hold of him, and said to him, "You of little faith, why did you doubt?" (Matt 14:31)

When they saw Him, they worshiped Him; but some were doubtful. (Matt 28:17)

Afterward He appeared to the eleven themselves as they were reclining at the table; and He reproached them for their unbelief and hardness of heart, because they had not believed those who had seen Him after He had risen. (Mark 16:14)

And He said to them, "Why are you troubled, and why do doubts arise in your hearts? (Luke 24:38)

A Believer's trust presents the possibility for God to do His work.

And Jesus answered and said to them, "Truly I say to you, if you have faith and do not doubt, you will not only do what was done to the fig tree, but even if you say to this mountain, 'Be taken up and cast into the sea,' it will happen. (Matt 21:21)

Truly I say to you, whoever says to this mountain, 'Be taken up and cast into the sea,' and does not doubt in his heart, but believes that what he says is going to happen, it will be granted him. (Mark 11:23)

Faith is deeply involved with, not only with the historical, but the contemporaneous reality of Jesus Christ; faith is not a hypothetical abstraction. Moreover, what Jesus says and does is at the direction of His Father and placing a trust in Jesus' words is placing a trust in God's word.

When the father of demon possessed son cries out, "I do believe; help my unbelief." (Mark 9:24), Jesus complies and heals the boy. The supernatural work demonstrates to the father that Jesus has the power of God, removes his doubt, and engenders a greater trust in Jesus' words.

Jesus spoke to one of disciples in regards to doubt:

Philip said to Him, "Lord, show us the Father, and it is enough for us." Jesus said to him, "Have I been with you for so long a time, and yet you have not come to know Me, Philip? The one who has seen Me has seen the Father; how can you say, 'Show us the Father'? Do you not believe that I am in the Father, and the Father is in Me? The words that I say to you I do not speak on My own, but the Father, as He remains in Me, does His works. Believe Me that I am in the Father and the Father is in Me; otherwise believe because of the works themselves. (John 14:8-11)