Why Did Jesus Say This Kind Can Only Come Out By Prayer and Fasting?
Short answer
In Mark 9:29, after the disciples fail to heal a boy with a violent, convulsing spirit, Jesus tells them privately that "this kind can come out only by prayer" — with many later manuscripts adding "and fasting." The point is not a magic technique but the disciples’ own overconfidence: earlier success (Mark 6:7–13) had let them rely on their own track record instead of sustained dependence on God, and this case exposed the gap.
The story sits at the base of the mountain where Jesus had just been transfigured (Mark 9:2–8). While He was away, a desperate father brought his son — seizing, foaming at the mouth, thrown into fire and water by a spirit that had tormented him "from childhood" (Mark 9:21) — to the remaining disciples, who could not help him.
Jesus arrives, casts it out with a word, and the disciples pull Him aside afterward, confused: they had done this before (Mark 6:7, 13). His answer, "this kind can come out only by prayer," is short, but it carries real weight once you notice what it corrects and what a well-known manuscript question adds to the picture.
A public failure after past success
What makes this account sting is that the disciples were not amateurs. Mark 6:7–13 records Jesus sending the Twelve out with authority over unclean spirits, and they succeeded. By Mark 9, that success had become recent history — which is exactly the problem Jesus names.
A crowd had gathered, teachers of the law were arguing with them (Mark 9:14), and the father’s plea — "if you can do anything" (Mark 9:22) — shows the public doubt building around their failure. Jesus’s broader response, "you unbelieving generation, how long shall I stay with you?" (Mark 9:19), lands on everyone present, not the boy’s father alone.
The manuscript question: "and fasting"
Careful readers notice a real difference between Bible translations here. The King James and New King James Versions read "prayer and fasting," while modern translations working from the oldest available Greek manuscripts (ESV, NIV, NRSV) read simply "prayer." Textual scholars widely regard "and fasting" as a later scribal addition, likely reflecting the early church’s growing practice of fasting rather than Jesus’s original wording — the phrase is absent from the earliest and most reliable manuscripts (Codex Sinaiticus and Vaticanus).
This is not a doctrinal crisis; fasting is commended elsewhere in Scripture on its own terms (Matthew 6:16–18, Acts 13:2–3). It simply means this particular verse’s textual history is worth knowing before quoting it as a fasting proof-text.
Why prayer (and fasting) matters here specifically
Jesus is not describing a two-step technique that guarantees results. "This kind" points to something about the severity or stubbornness of this particular case — language many readers take as pointing to a category of deeper spiritual opposition that resists a casual, confidence-based approach.
Prayer, in this context, is the posture of ongoing dependence on God’s power rather than a rehearsed method the disciples could run on their own strength. Where fasting is practiced alongside prayer in Scripture, it consistently functions the same way: not to earn God’s attention, but to strip away self-reliance and sharpen focus during a specific, weighty need (Ezra 8:21–23; Esther 4:16; Acts 14:23).
What this means for prayer today
You do not need to fast before every prayer, and Jesus never says results are earned by the discipline itself. What the account does teach is humility about spiritual authority: past answered prayer is not a credential you can coast on, and some situations — addiction, entrenched family conflict, a stubborn illness, a long-standing spiritual struggle — call for sustained, dependent prayer rather than a single confident request. If you are facing something that feels bigger than your usual prayer life has matched, this passage gives permission to slow down, pray longer, and, if it fits your tradition and health, fast — not as a formula, but as a way of putting your whole self behind the request.
Key Bible verses
- He replied, "This kind can come out only by prayer." (Some manuscripts add "and fasting.") — Mark 9:29
- Jesus said, "Everything is possible for one who believes." The boy’s father exclaimed, "I do believe; help me overcome my unbelief!" — Mark 9:23–24
- Calling the Twelve to him, he began to send them out two by two and gave them authority over impure spirits. — Mark 6:7
Frequently asked questions
What does "this kind can only come out by prayer and fasting" mean?
Jesus told His disciples that a particularly severe or stubborn spiritual struggle required real, sustained dependence on God — not a technique the disciples could run on their own strength or past success, which is exactly what had just failed them.
Why couldn’t the disciples cast out this demon?
Mark doesn’t give a single stated cause, but the context points to overconfidence: they had succeeded before (Mark 6:7–13) and appear to have approached this case the same way, without the depth of dependent prayer this particular situation required.
Does the Bible really say "and fasting" in Mark 9:29?
It depends on the translation. The oldest surviving Greek manuscripts read only "by prayer"; "and fasting" appears in later manuscripts and is preserved in the King James Version. Most modern translations follow the earlier text and omit it, though fasting is affirmed elsewhere in Scripture regardless.
Do I need to fast for God to answer my prayers?
No. Fasting is never presented in Scripture as a fee that purchases an answer. It is a discipline that sharpens focus and dependence during a specific need — valuable, but not a requirement for prayer to "work."