What Does Matthew 17:20 Mean?
Matthew 17:20 describes Jesus explaining why His disciples failed to heal a demon-possessed boy - they lacked faith. He tells them even a tiny amount of faith, like a mustard seed, can move mountains. This shows that real power comes not from skill or status, but from trusting God completely.
Matthew 17:20
He said to them, “Because of your little faith. 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.”
Key Facts
Book
Author
Matthew
Genre
Gospel
Date
circa 80-90 AD
Key People
Key Takeaways
- Small faith in God can overcome any obstacle.
- True power comes from trust, not human ability.
- Prayer and fasting strengthen faith for tough battles.
Context of the Disciples' Failed Healing Attempt
Right before Matthew 17:20, the disciples came down from the mountain of transfiguration and met a desperate father whose son suffered a severe demonic illness.
The man had already asked the disciples to drive out the demon, but they couldn’t do it - this failure comes right after a powerful moment where Peter, James, and John saw Jesus glorified and heard God’s voice, making their inability to heal the boy even more striking. Jesus responds by calling them a 'faithless and twisted generation' and brings the boy to himself, instantly healing him when the disciples could not.
This sets the stage for Jesus’ explanation in verse 20: their lack of faith, not lack of technique or authority, was the real problem - and even a tiny, mustard-seed-sized trust in God can accomplish what seems impossible.
Understanding 'Mustard-Seed Faith' and 'Moving Mountains' in Jesus' Teaching
Jesus’ words about mustard-seed faith and moving mountains aren’t meant to be taken as literal gardening or geography lessons, but as vivid images His listeners would have instantly recognized from their own culture and Scripture.
In Jewish teaching of the time, the mustard seed was a common symbol for something tiny yet full of potential - it was the smallest seed people regularly planted, so rabbis often used it to illustrate how small beginnings could lead to big results. Likewise, 'moving mountains' was a stock expression for overcoming impossible obstacles, not a command to reshape the landscape. Other Jewish writings used similar phrases to describe removing spiritual or social barriers. Jesus used these familiar images to show that faith isn’t about quantity or human effort, but about trusting in God’s limitless power.
Even the smallest real faith can unlock God’s power because it’s not about size - it’s about who you trust.
What matters is not how much faith you have, but the faithfulness of the One you trust. This also fits with what Jesus adds in verse 21 - that some challenges, like this kind of demon, require deeper spiritual discipline like prayer and fasting, showing that real faith is active and rooted in closeness to God. This prepares us for the next part of the story, where Jesus again turns to His coming suffering - reminding us that true power in God’s Kingdom often looks like humility and sacrifice.
Trusting God in Prayer: The Simple Power Behind Impossible Change
This story fits Matthew’s larger message that true spiritual power comes not from status or ritual, but from humble trust in God and a life of prayerful dependence.
Matthew often highlights how Jesus values heart-level faith over outward performance, and this moment - where even the disciples fall short - shows that no one is immune to weak faith. The lesson is clear: when we face hard things, God calls us to rely on Him through prayer rather than trying harder on our own.
This prepares us for Jesus’ next teaching about His coming suffering - because even He, the Son of God, faced the cross with prayer and surrender, showing us the way to live by faith.
Faith That Moves Mountains: Jesus Fulfills the Promise of Divine Power
This moment with the disciples echoes through the New Testament, showing that true spiritual power isn’t found in status or strength, but in humble trust in Christ - the one who fulfills God’s plan.
Paul picks up Jesus’ mountain-moving language in 1 Corinthians 13:2 when he says, 'If I have all faith, so as to remove mountains, but have not love, I am nothing.' He isn’t contradicting Jesus; he is deepening His teaching. Even the most powerful faith means nothing without love, showing that Jesus’ way is about heart transformation, not merely miraculous power. Likewise, in Mark 11:23-24, Jesus says, '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 will come to pass, it will be done for him. Therefore I tell you, whatever you ask in prayer, believe that you have received it, and you will.' These passages confirm that 'moving mountains' illustrates radical trust in God’s power through prayer, rooted in relationship, rather than a one-time miracle.
Even the smallest faith in Jesus unleashes divine power because it connects us to the One who fulfills all God’s promises.
This prepares us for Jesus’ next words about His coming death and resurrection - because the greatest 'impossible' thing wasn’t moving a mountain, but raising Himself from the dead, the ultimate act of faith and love that makes all other promises possible.
Application
How This Changes Everything: Real Life Impact
I remember a time when I was overwhelmed by a financial crisis - bills piling up, no clear way forward. I prayed, yes, but mostly out of duty, not real trust. I knew the words, but deep down I doubted God would actually move. Then I read Matthew 17:20 again and it hit me: my problem wasn’t the size of my faith, but the object of it. I’d been trusting my own ability to fix things, not God’s power to make a way. When I shifted - even with a tiny, shaky trust - I began praying with honesty and hope instead of desperation. And slowly, doors opened: a surprise payment, a lowered bill, peace in the storm. It wasn’t a mountain jumping into the sea, but it felt like one had been lifted off my chest. That’s the power of mustard-seed faith: it’s not about feeling strong, but leaning hard on the One who is.
Personal Reflection
- Where in my life am I trying to 'perform' faith rather than trusting God, even in small ways?
- What 'impossible' situation am I facing that I haven’t truly brought to God in prayer, believing He can move it?
- How can I grow my daily dependence on God in ordinary moments as well as big crises?
A Challenge For You
This week, pick one worry or problem you’ve been carrying alone. Each day, pray with a single sentence of trust - like, 'God, I don’t see how, but I believe You can handle this.' Pair it with a small act of surrender, like writing it down and putting it in an envelope as a symbol of releasing it to Him.
A Prayer of Response
God, I admit my faith is often weak. I try to fix things on my own and forget to trust You. Thank You that even a tiny bit of real faith in You can make a difference. Help me depend on You more each day, especially when life feels impossible. Teach me to pray with honesty, trust, and hope, knowing You are always with me.
Related Scriptures & Concepts
Immediate Context
Matthew 17:18-19
Jesus heals the demon-possessed boy instantly, prompting the disciples' question about their failure.
Matthew 17:21
Jesus explains that prayer and fasting are needed for certain spiritual battles.
Connections Across Scripture
Luke 17:6
Jesus uses the same mustard seed image to show faith’s potential when rooted in God.
Hebrews 11:1
Faith is the assurance of things hoped for, grounding the concept behind mustard-seed trust.
Isaiah 40:29
God gives strength to the weary, showing His power is accessed through dependence, not might.