And when he was entered into the house, his disciples asked him privately, Wherefore could not *we* cast him out?
The disciples wait until they are indoors with Jesus, away from the crowd. Only then do they ask why they had failed. His answer does not deal with method. It goes to the state of their souls.
Asking Him in private was their habit, not a one-off.
The apostles sometimes used moments of His privacy to lay their difficulties before Him. They came to Him "apart" to learn why they were unable to cast the demon out of a young man (Matt. 17:19; Mark 9:28).
They had done this work before, using authority He Himself gave them.
When the Lord sent out the Twelve, He "gave them power over unclean spirits," and for a time they used this power, for we read, "they cast out many devils" (Mark 6:7, 13). Here, however, their faith failed. They could not cast out the dumb spirit. There was power present to work miracles and to overcome all the power of Satan. But man could not profit by it, and the disciples had no faith to use it.
He names one cause: unbelief. Then He shows how little faith it would have taken.
It lies on the surface: they did not know how to use the power their Lord had given them. He plainly tells them the cause of this was their unbelief. He leads their hearts so clearly into the secret of their failure that He adds, "For truly, I say to you, if you have faith like a grain of mustard seed, you will say to this mountain, 'Move from here to there,' and it will move; and nothing will be impossible for you." So without faith at work, there can be no display of power through the servant, whatever his earnestness or zeal for the glory of God.
Later in the same chapter the disciples argue on the road about who is greatest, and one writer ties that argument directly to their weakness at the foot of the mountain.
He came to Capernaum, and while in the house He asked them, "What were you discussing on the way?" "But they kept silent, for on the way they had argued with one another about who was the greatest." No wonder there was little power in the presence of Satan; no wonder there was little understanding in the presence of Jesus. There was a dead weight behind — this spirit of thinking about themselves, of wanting some distinction to be seen and known by men now.
Both prayer and fasting mean something deeper than a religious exercise.
Prayer is the realisation of complete dependence, and the expression of that dependence before God. It goes with confidence in Him, and with the expectation that He will answer our cries. True prayer, therefore, assumes that we have come to the end of ourselves, of our own wisdom and of our own strength. As long as we have the slightest trust in ourselves — in our own skill, way of serving, manner of speech, or natural abilities — we cannot be wholly cast upon God. By "fasting" we are to understand, not simply going without food, but the refusal of the things of this world we are passing through.
One writer counts three ways our position today matches theirs.
First, the Lord is absent in both cases. Second, we, like them, are continually in the presence of Satan's power — seen, sadly, sometimes among Christians, and always in the souls of the unconverted. And last, God gives us power greater than all the strength of the enemy (Ephesians 6:10-18; 1 John 4:4), as much as He gave the disciples, if not more.
Failure like theirs is not the end of the matter.
Again and again we ought to be asking their question, as we find ourselves weak in the presence of the foe; and as we do, we will no doubt get exactly the answer they got.
- Ask — the disciples took their failure straight to Christ in private. Bringing our difficulties to Him is the first step back.
- Given — the power was never withdrawn; they had cast out demons before. What failed was the faith to use what was already theirs.
- Root — the Lord names unbelief. Behind it sat a dead weight: their wish to be seen as the greatest. Faith the size of a mustard seed would have been enough. The shortfall is never in His power.
- Soil — faith grows in complete dependence (prayer) and in refusing what this world offers (fasting). Any trust left in our own skill keeps us from being wholly cast upon God.
- Us — the Lord is absent, the enemy is active, the power is ours. When we stand powerless, their question is our question, and His answer is our answer.
And he said to them, This kind can go out by nothing but by prayer and fasting.
The Lord had given His disciples authority over unclean spirits. Yet in front of a crowd they could not free one boy, and later they asked Him in private why. His answer points them not to a better method, but to the state of soul that lets the power already in their hands work.
The failure was not a shortage of power, but a shortage of faith to draw on it.
When the Lord sent out the twelve disciples, He "gave them authority over the unclean spirits." For a time they used this power, for we read, "they cast out many demons" (Mark 6:7, 13). Here, however, their faith failed. They could not cast out the mute spirit. The power to work miracles and overcome all the power of Satan was present. But man could not gain from it, and the disciples had no faith to use it.
Underneath the unbelief lay something more specific — they had stopped leaning on God.
The Lord shows that, along with the unbelief, there is a lack of the sense and confession of dependence on God. This alone also judges the strength of our own nature. "This kind," He says, "can go out by nothing but by prayer and fasting." The power is in Jesus, and faith alone draws it out. But that faith carries the sentence of death on our own nature, along with the look up to God, the only source of power.
Older translations read "by prayer and fasting" here. The two words name two halves of one attitude, and fasting reaches wider than food.
Prayer is how a soul, confident in God, puts into words its awareness of complete dependence. Fasting will mean that Nazarite condition which refuses lawful things and lawful pleasures (see Numbers 6:3-7) for the sake of fuller devotion to the Lord's service. It may sometimes include going without food, but to limit it to that is to miss its main point. A fasting soul is one so filled with the richness of heavenly joys that it rises above the pleasures of earth and does not need them.
Put another way, one word is the positive side and the other the negative side of a single faith.
There are therefore different kinds of spirits. However, the connection of this verse and verse 19 shows that we are faithless if we lack prayer and fasting. For prayer expresses dependence on God, while fasting emphasizes self-denial or no confidence in the flesh.
The words "this kind" set this case apart from others.
It was indeed a mighty deed, and so it fell to this Gospel, more than the others, to give the most details. Evil spirits differ from one another, and this kind gave way only to prayer and fasting. That lack grieved the Lord.
Not every early copy of Mark carries the words "and fasting". The writer who points that out still holds fasting's worth.
The Lord does not so much command fasting as bring it, like prayer, under the Christian principle of dealing with our Father in secret… He also points to its value for spiritual power. Godly people have always felt, and must feel, how fitting it is for humbling the soul before God, when public or private need called for such humbling. But even in Mark 9:29 it is worth noting that the two oldest copies leave out "and fasting". Those copies, with other authorities, also leave out the whole of verse 21 in Matthew 17, and there is no matching word in Luke 9.
Fasting takes shape when someone gives up a lawful thing for the sake of God's work.
What does fasting mean? In practice, does it not mean giving up things that are lawful in themselves but not helpful, as the soul takes in the real presence of God, what suits Him, and what His work needs?… Missionaries live far from home ties that are lawful in themselves. Do they not cut themselves off from ease, comfort, companionship and the fellowship of fellow believers at home, to carry the gospel to people who have never heard it? I knew one young man who fasted from a hobby he loved, to give the money and time he saved to the Lord.
The disciples asked in private and got an answer. Our weakness should send us to the same place.
We ought to ask their question again and again, whenever we find ourselves weak in the presence of the enemy. As we do, we will surely get the same answer they got in verse 29. The Lord had already said that unbelief lay at the root of their powerlessness. Now He names two more things. Faith is needed, and so are prayer and fasting.
- Power — the disciples already had authority over unclean spirits. What failed was the faith to use it.
- Dependence — prayer says that dependence out loud: the power is in Christ, not in us.
- Denial — fasting is the other half: giving up lawful things, so that nothing of self competes with devotion to His service.
- Degrees — "this kind" shows that some battles yield only to that state of soul, and its absence grieved the Lord.
- Diagnosis — when we are weak before the enemy, ask the disciples' question and expect the same answer.