Mark 9:28-29 · Bible study
Mark 9:28-29 Commentary: Why Prayer & Fasting? Study
Greek · 7 what the commentators say
Meaning in one sentence
The disciples had authority over demons, so why did they fail? Jesus explains that some spiritual battles require prayer and fasting.
Research Summary
- Meaning: The disciples had authority but lacked the spiritual discipline required for a particularly stubborn demon; Jesus redirects them to prayer and fasting as the context for effective ministry.
- Key words: γένος (kind, class of spirit); προσευχή (prayer addressed to God); νηστεία (voluntary fasting as religious exercise); δύναμαι (to be able, implying inherent power or permission).
- Main debate: Whether Jesus refers to a distinct rank of demons requiring extraordinary measures, or to any deeply rooted evil (including habitual sin) that yields only to intense spiritual disciplines.
- Theological theme: Spiritual authority is not automatic; it must be sustained by ongoing communion with God and self-denial. Grace empowers effort; effort does not earn grace.
- Best use: A warning against presumption in ministry and an invitation to deepen dependence on God through consistent prayer and occasional fasting.
Translation Comparison
BSB Berean Standard Bible 2020
28After Jesus had gone into the house, His disciples asked Him privately, “Why couldn’t we drive it out?”
29Jesus answered, “This kind cannot come out, except by prayer.”
WEB World English Bible 2000
28When he had come into the house, his disciples asked him privately, “Why couldn’t we cast it out?”
29He said to them, “This kind can come out by nothing but by prayer and fasting.”
KJV King James Version 1769
28And when he was come into the house, his disciples asked him privately, Why could not we cast him out?
29And he said unto them, This kind can come forth by nothing, but by prayer and fasting.
ASV American Standard Version 1901
28And when he was come into the house, his disciples asked him privately, How is it that we could not cast it out?
29And he said unto them, This kind can come out by nothing, save by prayer.
YLT Young's Literal Translation 1898
28And he having come into the house, his disciples were questioning him by himself--`Why were we not able to cast it forth?'
29And he said to them, `This kind is able to come forth with nothing except with prayer and fasting.'
Darby Darby Bible 1890
28And when he was entered into the house, his disciples asked him privately, Wherefore could not we cast him out?
29And he said to them, This kind can go out by nothing but by prayer and fasting.
Douay-Rheims Douay-Rheims Bible 1899
28And he said to them: This kind can go out by nothing, but by prayer and fasting.
29And departing from thence, they passed through Galilee: and he would not that any man should know it.
Verse in Context
Original Language (Koine Greek)
New Testament · Koine Greek · Mark 9:28
Source: STEPBible TAGNT/TEHB (CC-BY 4.0). Click or tap a morphology code to see the full parsing.
Scholars' Consensus
Commentators across traditions agree that these verses address a specific failure. The disciples had been given authority over unclean spirits (Luke 9:1) and had previously cast out many demons, but this particular case defeated them. The Cambridge Bible notes that Jesus impresses two lessons: the omnipotence of perfect faith and that there are degrees of wickedness among evil spirits, some so intense that they require spiritual preparation beyond ordinary faith. Jamieson-Fausset-Brown says 'this kind of evil spirits cannot be expelled' without prayer and fasting, and links the failure to the disciples' unbelief, as Matthew 17:20 makes explicit. Adam Clarke treats the demon as an emblem of deeply rooted vices and 'inveterate habits' that yield only to extraordinary humiliations. Gill points out that the disciples feared they had lost their power; Jesus corrects them by pointing to what they had not done, prayed and fasted. The consensus is that Jesus does not revoke their authority but teaches that effective exercise of that authority depends on sustained, self-denying communion with the Father.
How settled is the interpretation?
Interpretive difficulty: Medium
Main views:
- Hierarchy of evil spirits: The word γένος, combined with Ephesians 6:12 and the clear distinction between this demon and others the disciples had cast out, suggests a ranking of spiritual powers.
- Symbolic reading (deep-rooted sin): Adam Clarke treats the demon as 'an emblem of deeply rooted vices' that require prolonged self-humiliation and extraordinary prayer, not a literal class of spirit.
- Textual critical view: If the original text lacked 'and fasting', then Jesus’ answer may have focused solely on prayer, and fasting was added later as a practical gloss. This would shift the emphasis from two practices to one.
What is clear: Jesus teaches that spiritual ministry cannot be performed with mere technique or past success; the disciples needed a deeper, disciplined dependence on God—whether through prayer alone or prayer with fasting.
What Scholars Agree and Debate
| Topic | Agreed | Debated |
|---|---|---|
| Meaning of 'this kind' | Jesus uses γένος to indicate a category or type of evil spirit, not simply any demon but one with particular tenacity or severity. | Some commentators (Cambridge, JFB) see a hierarchy of evil spirits, citing Ephesians 6:12; others (Adam Clarke) read it as emblematic of deeply rooted personal vices or sinful habits. Both sides agree the phrase points to an exceptional spiritual challenge. |
| Role of fasting | Fasting intensifies prayer by focusing the believer on God and breaking physical dependencies. It is a legitimate biblical practice. | Catholic and Orthodox traditions include regular fasting as a normative spiritual discipline; some Protestant traditions treat it as optional or circumstantial. The text is read by most as prescriptive for believers facing similar opposition, while a few see it as descriptive only for the apostles' post-Pentecost ministry. |
| Relationship to faith | Faith is essential for all ministry; the disciples lacked the specific faith needed here. | Matthew 17:20 attributes the failure to unbelief; Mark 9:29 attributes it to the absence of prayer and fasting. Some harmonize by seeing prayer and fasting as the training ground for greater faith. Others hold that the two accounts present complementary truths, faith as the source, disciplines as the means. |
| Textual authenticity of 'and fasting' | The phrase 'and fasting' appears in the majority of manuscripts and is quoted by numerous Church Fathers. | The shorter reading (without 'and fasting') is found in Codex Sinaiticus and a few other early witnesses, leading some textual critics to consider it original. Most English translations (WEB, KJV, NIV) retain it; the ASV brackets it as uncertain. |
| Application for today | Prayer and fasting remain valuable spiritual disciplines for all Christians. | Churches that emphasize deliverance ministry often treat this verse as a practical directive for exorcism; others interpret it more broadly as a call to any believer facing seemingly insurmountable obstacles, whether sin, sickness or spiritual oppression. |
Historical & Cultural Context
The scene unfolds in the private space of a house (εἰς οἶκον), a pattern in Mark's Gospel where Jesus explains matters away from the crowd (Mark 4:10, 4:34, 7:17). This privacy after the public failure at the foot of the mountain frames the disciples' question as an anxious one, 'Why couldn't we?' They had recently succeeded in exorcisms during their mission (Mark 6:7, 6:13), so this defeat was deeply troubling.
The story follows directly from the Transfiguration and a confrontation between Jesus, the scribes and a distressed father. Verse 24 records the father's cry, 'I believe; help my unbelief!', a confession that highlights the faith needed even in desperation. When the disciples' own faith wavered, they could not access the power that Christ had delegated to them.
Jewish exorcistic practices often involved elaborate prayers and ritual purity, including fasting. Fasting (νηστεία) was a recognized discipline for seeking God's favor in times of crisis (Joel 1:14) and for intensifying prayer. Jesus' words here align with a tradition that certain demonic strongholds require more than a simple command, they demand prayer that is itself disciplined and undistracted. The disciples had relied on their previous experience and perhaps a routine authority, but this case exposed a gap between delegated power and the personal holiness needed to wield it effectively. By sending them back to prayer and fasting, Jesus redirects them from technique to relationship.
Textual Notes
The phrase 'and fasting' (καὶ νηστείᾳ) is present in the majority of Greek manuscripts and in most ancient versions (Old Latin, Vulgate, Syriac). However, it is absent from Codex Sinaiticus (ℵ, 4th century) and a few other witnesses, including some manuscripts of the Old Latin. The shorter reading is likely original; scribes may have added 'and fasting' to harmonise with Matthew 17:21, which also includes the phrase. Yet because the longer reading is so widespread and appears early, many conservative scholars retain it as authentic. The ASV and some modern translations print the shorter text with a note. In either case, the surrounding narrative and the parallel in Matthew strongly associate prayer with spiritual preparation, and fasting was a natural expression of that preparation in the early church.
Reception History
From the early church onward, this passage has been central to teaching on spiritual warfare. Origen and John Chrysostom cited it as evidence that some demons resist ordinary exorcism. In the medieval period, monastic communities read it as a call to the 'greater asceticism' needed for deliverance ministry. The Reformation stressed that prayer and fasting do not earn power but create dependence on God; Calvin saw them as means of stirring up faith. In modern evangelical and charismatic circles, these verses are often key texts for deliverance seminars and teaching on spiritual disciplines. Catholics and Orthodox have used them to support regular fasting in the liturgical year. Across traditions, the verse functions as both a comfort, failure is not final, and a challenge: deeper battles require deeper devotion.
Preaching This Verse
Three-point outline
- Privilege does not guarantee power. The disciples had authority on paper, but they could not exercise it. Their question reveals confusion: 'We could cast out demons before, why not now?'
- Not all spiritual opposition is equal. Jesus uses the word γένος (kind, sort) to indicate a class of evil spirits with particular tenacity. Some battles require greater spiritual resources than others.
- Prayer and fasting align the servant with the Master. These disciplines do not manipulate God; they humble the practitioner and focus trust entirely on Christ. The disciples had the authority but lacked the focused dependence that generates faith.
Five-point outline
- The private question: The disciples wait until they are alone with Jesus, a model for bringing our failures to Him honestly.
- The humbling admission: Their question is not 'why didn't You help us?' but 'why could not we?' They take responsibility for the failure.
- The specific reply: Jesus does not accuse them of losing their gift. He identifies a missing preparation, not a missing commission.
- The nature of 'this kind': Some forms of evil are more entrenched, whether in individuals or in systems. Recognising the enemy's strategy matters.
- The prescribed disciplines: Prayer connects us to God's power; fasting breaks earthly dependencies. Together they forge a vessel fit for the Master's use.
Illustration hooks
- A tradesman who knows how to use his tools but neglects sharpening them. The blade is still his, but the cut needs force that the edge no longer supplies.
- A parent who has authority over their teenager but loses influence when communication breaks down. The authority is still real, but relationship must be restored for it to work.
- An athlete who wins regularly but faces a stronger opponent. The same skills are needed, but a more intense training prepares them for the specific challenge.
Questions your congregation is asking
- If I have God's power through the Holy Spirit, why do I still fail in certain areas of life or ministry?
- Should fasting be a regular part of my spiritual life, or only when facing a 'big problem'?
- How do I know whether a struggle is normal or a 'this kind' situation that demands extra prayer?
Leading a Discussion
This passage invites honest reflection on the gap between what God has given us and what we actually experience. The disciples were not novices; they had already exercised authority over demons. Yet they met a case that stopped them. Their response was to go to Jesus privately, not to defend themselves, but to learn. As you discuss, let the question be: what do we rely on when our usual resources run dry?
Discussion questions
- Read Mark 9:14, 29 as a whole. What do you notice about the father, the disciples, the crowd, and Jesus? How do their responses differ?
- The disciples ask privately: 'Why couldn't we cast it out?' Why do you think they waited until they were alone? What does that tell you about their relationship with Jesus?
- Jesus answers: 'This kind can come out by nothing but by prayer and fasting.' What do you think 'this kind' means? A type of demon, or a level of difficulty?
- How does this verse connect to Matthew 17:20, where Jesus says 'because of your unbelief'? Are prayer and fasting a way to increase faith, or a sign of existing faith?
- In your own experience, when have you tried to do something in your own strength that required deeper dependence on God? What was the outcome?
- Fasting is rarely practiced in many churches today. What keeps Christians from fasting? What would change if we took this command more seriously?
- How can a small group support one another in cultivating a life of prayer and, when needed, fasting?
Word Study
The key original-language words in this verse. Select any word for its full lexicon entry — meaning, every occurrence in Scripture, and related words.
Cross-References
Source: Treasury of Scripture Knowledge (TSK, public domain)
| Matthew 13:10 | The disciples came, and said to him, “Why do you speak to them in parables?” |
| Matthew 13:36 | Then Jesus sent the multitudes away, and went into the house. His disciples came to him, saying, “Explain to us the parable of the darnel weeds of the field.” |
| Matthew 15:15 | Peter answered him, “Explain the parable to us.” |
| Matthew 17:19 | Then the disciples came to Jesus privately, and said, “Why weren’t we able to cast it out?” |
| Matthew 17:20 | He said to them, “Because of your unbelief. For most certainly I tell you, if you have faith as a grain of mustard seed, you will tell this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you. |
| Mark 4:10 | When he was alone, those who were around him with the twelve asked him about the parables. |
| Mark 4:34 | Without a parable he didn’t speak to them; but privately to his own disciples he explained everything. |
| Mark 7:17 | When he had entered into a house away from the multitude, his disciples asked him about the parable. |
Interlinear and lexical data from STEPBible (CC BY 4.0). Cross-reference data from OpenBible.info (CC BY 4.0). Commentaries are public domain.
For personal reflection
Read the devotional page — prayer, application, and "for families"
What the Commentators Say
5 public-domain commentaries, condensed into plain language.
Adam Clarke's Commentary Methodist/Wesleyan 1826
Clarke sees this demon as an emblem of deeply rooted vices and stubborn habits that usually require extraordinary self-humbling to overcome. He also observes that Mark's account adds many new circumstances, showing that Mark did not simply abridge Matthew.
Geneva Bible Notes Reformed 1599
The Geneva annotators highlight Jesus' specific answer that "this kind" of demon requires prayer and fasting, implying not all spiritual battles yield to the same level of exertion. The disciples' failure is attributed to insufficient preparation, teaching that some victories demand deeper devotion and self-denial.
Gill's Exposition of the Bible Baptist 1748
Gill observes that Mark records only prayer and fasting as Jesus' reason the disciples could not cast out the demon, while Matthew mentions unbelief as well. For Gill, this means the disciples' failure was specifically their neglect of these spiritual practices that this kind of evil spirit requires.
Jamieson-Fausset-Brown Commentary Protestant 1871
JFB treats Jesus' mention of prayer and fasting as pointing to the effort needed for special spiritual victories. Even strong faith must be cultivated through sustained prayer and self-denial to reach the height required for such triumphs; it is not a mechanical requirement but a matter of disciplined preparation.
Lange's Commentary Reformed 1857
Lange highlights how Jesus deliberately calms the crowd and the father before addressing the deeper issue: for Christ, ability and belief are the same thing. The father's cry, "I believe; help my unbelief," becomes the model of genuine faith that acknowledges its own weakness and reaches toward greater trust.