05/04/2026
A Sermon on Matthew 17:20 (NKJV)
Presbyter Paul Ndirangu
Sunday, 5th April 2026
Introduction
Good morning, church family. I want you to imagine for a moment that you're standing at the base of Mount Kenya. Three thousand five hundred meters of solid rock and ice towering above you, seemingly immovable, seemingly impossible to conquer. Now imagine someone walking up to you and saying, "Speak to that mountain, and it will move." Your first reaction would probably be laughter, followed by a polite suggestion that they seek professional help.
Yet this morning, we're going to explore one of the most audacious, most challenging, and most transformative promises that Jesus ever made to His disciples—and to us.
Turn with me to Matthew 17:14–21 (NKJV).
14 And when they had come to the multitude, a man came to Him, kneeling down to Him and saying, 15 “Lord, have mercy on my son, for he is an epileptic and suffers severely; for he often falls into the fire and often into the water. 16 So I brought him to Your disciples, but they could not cure him.” 17 Then Jesus answered and said, “O faithless and perverse generation, how long shall I be with you? How long shall I bear with you? Bring him here to Me.” 18 And Jesus rebuked the demon, and it came out of him; and the child was cured from that very hour. 19 Then the disciples came to Jesus privately and said, “Why could we not cast it out?” 20 So Jesus said to them, “Because of your unbelief; for assuredly, I say to you, if you have faith as a mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you. 21 However, this kind does not go out except by prayer and fasting.”
Nothing will be impossible for you.
Let that sink in. The Son of God, the Creator of the universe, the One who spoke the mountains into existence, is telling His followers—telling us—that there is a kind of faith that makes the impossible possible, that moves the immovable, that transforms the unchangeable.
But here's what strikes me about this passage: Jesus doesn't begin with the promise; He begins with the problem. "Because of your unbelief."
This morning, I want us to journey together through what I'm calling "The Mountain-Moving Faith," and we're going to discover three life-changing truths:
- First, we must understand the problem of unbelief that keeps us powerless.
- Second, we must understand the solution of mustard seed faith that makes us powerful.
- And third, we must understand the promise of mountain-moving power that makes us unstoppable.
I. Understanding the Problem: The Paralysis of Unbelief
Let's begin by understanding the context of this remarkable verse. Just before this statement, the disciples had encountered a father whose son was tormented by a demon. This wasn't a minor spiritual skirmish—this was a desperate situation. The boy would throw himself into fire and water, convulsing, foaming at the mouth, grinding his teeth. The father had brought his son to the disciples, expecting them to have the power to heal, but they couldn't do it.
Can you imagine the embarrassment? These were the same disciples who had been given authority over unclean spirits. They had seen Jesus cast out demons with a word. They had even done it themselves before. But now, when faced with this particular mountain of spiritual opposition, they were powerless.
When Jesus arrives on the scene, He doesn't just heal the boy—He rebukes the entire generation, calling them "faithless and perverse." Then, after demonstrating His power by casting out the demon instantly, the disciples came to Him privately, desperately asking, "Why could we not cast it out?"
And that's when Jesus delivers this devastating diagnosis: "Because of your unbelief."
Church, unbelief is not simply the absence of faith—it's the presence of doubt that actively opposes faith. It's not just failing to believe; it's choosing to believe the opposite of what God has said. Unbelief doesn't just leave us neutral; it leaves us negative, powerless, and defeated.
Look at how unbelief had paralysed these disciples. They had the right knowledge—they knew about spiritual authority. They had the right credentials—they were Jesus' chosen disciples. They had the right intentions—they wanted to help this desperate father. They even had the right methods—they tried to cast out the demon. But they had the wrong heart condition. Unbelief had crept in like a virus, infecting their confidence and crippling their effectiveness.
a) Here's what I've learned about unbelief:
i. It's not usually dramatic or obvious. It doesn't announce itself with trumpets and fanfare. Instead, it whispers quietly in the background of our minds. It says things like, "Sure, God can do miracles, but not in my situation." Or "Yes, God answers prayer, but probably not for someone like me." Or "I know God is powerful, but this mountain I'm facing is different—it's too big, too old, too complicated."
ii. Unbelief specialises in making exceptions. It will acknowledge God's general power while denying His specific power in your particular situation. It will accept His past miracles while rejecting His present possibilities. It will believe His promises for others while questioning His promises for you.
b) And here's the tragic result:
When unbelief takes root, we become like those disciples—going through the motions without experiencing the miracles, having the form of godliness but denying its power, standing before mountains that should move but remaining frustratingly, heartbreakingly still.
II. Understanding the Solution: The Power of Mustard Seed Faith
But notice how Jesus doesn't leave His disciples—or us—in despair. After diagnosing the problem, He immediately provides the solution: "If you have faith as a mustard seed..."
The mustard seeds are incredibly small. We're talking about something roughly the size of a dot at the end of this sentence. In Jesus' day, the mustard seed was commonly used as a metaphor for the smallest of things. It was tiny, almost insignificant, easily overlooked.
But here's what Jesus is teaching us:
- Faith is not about size; it's about the source.
- Faith is not about quantity; it's about the quality.
- Faith is not about how much you have; it's about where you place it.
You see, the disciples were looking at their faith like it was a muscle that needed to be bigger and stronger. They thought they needed more faith, better faith, perfect faith. But Jesus is telling them—and us—that even the tiniest, most seemingly insignificant faith, when properly placed, can accomplish the impossible.
Think about what makes a mustard seed powerful. It's not its size—it's its life. Inside that tiny seed is the genetic code, the DNA, the life force that will produce a tree large enough for birds to nest in its branches. The power isn't in the seed itself; the power is in what the seed connects to—the life-giving force that causes it to grow.
- Similarly, the power of faith is not in our believing; it's in the One we believe in.
- Faith is not a force we generate; it's a connection we make.
- Faith is not about working up enough spiritual energy to move mountains; it's about linking up with the God who spoke the mountains into existence in the first place.
Here's the beautiful truth that Jesus is revealing:
- You don't need great faith in a great God; you need genuine faith in a great God.
- You don't need to feel confident; you need to be connected.
- You don't need to be sure of your faith; you need to be sure of your Father.
The woman with the issue of blood
I think about that woman with the issue of blood in Mark chapter 5. She had been bleeding for twelve years, had spent all her money on doctors, and was getting worse instead of better.
- She didn't have great faith—she had desperate faith.
- She didn't have perfect theology—she thought she could be healed just by touching Jesus' clothes. (unclean touching the cleanest)
- But she had genuine faith in the right Person, and when her tiny faith connected with His unlimited power, she was instantly and completely healed.
- Practical faith is when our active tiny faith connects with His unlimited power.
That's mustard seed faith. It's not about the size of your faith; it's about the size of your God. It's not about how much you believe; it's about whom you believe in. It's not about feeling strong; it's about being connected to the Strong One.
III. Understanding the Promise: The Reality of Mountain-Moving Power
Now we come to the most audacious part of Jesus' statement: "You will say to this mountain, 'Move from here to there,' and it will move; and nothing will be impossible for you."
Let me ask you something: What mountains are standing in your life right today? I'm not talking about the geological kind—I'm talking about the spiritual, emotional, relational, and circumstantial mountains that seem immovable, impossible, and insurmountable.
Maybe it's the mountain of addiction that has held someone you love captive for years. Maybe it's the mountain of financial debt that seems to grow larger every month, no matter how hard you work. Maybe it's the mountain of a broken marriage that appears beyond repair. Maybe it's the mountain of a medical diagnosis that the doctors say is terminal. Maybe it's the mountain of depression or anxiety that has overshadowed your joy for too long.
Jesus is saying that these mountains—whatever they are—don't have to be permanent. They don't have to define your destiny. They don't have to determine your future. When mustard-seed faith connects with the mountain-moving God, the impossible becomes possible.
*Philippians 2:9–11 (NKJV): 9 Therefore God also has highly exalted Him and given Him the name which is above every name, 10 that at the name of Jesus every knee should bow, of those in heaven, and of those on earth, and of those under the earth, 11 and that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.*
But notice something crucial about Jesus' promise: "You will say to this mountain..."
- Faith always involves speaking. It's not just believing in your heart; it's declaring with your mouth.
- It's not just hoping quietly; it's proclaiming boldly.
- It's not just wishing things would change; it's speaking the change you want to see.
Why is speaking so important?
- Because words have power.
- God created the universe with words.
- Jesus calmed storms with words.
- The early church turned the world upside down with words.
- And Jesus is telling us that when we speak with mustard seed faith, our words become vehicles for God's mountain-moving power.
But here's what we must understand:
- This is not about positive thinking or mind over matter or some kind of cosmic ordering system.
- This is about aligning our words with God's will, our declarations with His desires, our proclamations with His purposes.
When we speak to mountains with mustard seed faith, we're not trying to manipulate God into doing what we want. We're positioning ourselves to cooperate with what God wants to do. We're not attempting to force our will on heaven; we're allowing heaven's will to flow through us to earth.
And notice the scope of Jesus' promise: "Nothing will be impossible for you." Not "some things will be possible" or "a few things might happen" but "nothing will be impossible."
When mustard seed faith connects with the God of impossibilities, every limitation becomes a possibility, every barrier becomes a bridge, every obstacle becomes an opportunity.
Practical Application and Conclusion
So how do we move from understanding these truths to living these truths? How do we cultivate mustard seed faith in our daily lives?
1. First, we must identify our unbelief. What lies have you been believing about your situation? Where have you made exceptions to God's power? What mountains have you accepted as permanent that God wants to move as temporary? Unbelief thrives in darkness, but it dies in the light of honest examination.
2. Second, we must plant seeds of faith. Start small. Begin with the tiny seed of faith you do have, not the great faith you wish you had. Connect that small faith to the great God who loves you. Remember, it's not about the size of your faith; it's about the size of your God.
3. Third, we must speak to our mountains. Stop talking about your mountains and start talking to them. Stop describing their size and start declaring their defeat. Stop explaining why they can't move and start proclaiming that they must move. Speak to the mountain of fear in your heart. Speak to the mountain of sickness in your body. Speak to the mountain of division in your family. Speak to the mountain of lack in your finances.
But remember this:
- We speak to mountains not because we have great faith, but because we serve a great God.
- We don't speak from our strength; we speak from His strength.
- We don't speak in our authority; we speak in His authority.
- We don't speak according to our power; we speak according to His power.
Church, I want to leave you with this thought:
- The same Jesus who spoke these words to His disciples is speaking these words to you today.
- The same power that was available to them is available to you.
- The same God who moved mountains for them wants to move mountains for you.
But it all begins with mustard seed faith. Not perfect faith. Not great faith. Not faith without questions or doubts. Just genuine faith in the right Person.
So let me ask you:
- What mountain is Jesus calling you to speak to today?
- What impossible situation is He inviting you to trust Him with?
- What insurmountable obstacle is He ready to turn into a testimony of His power?
Don’ts
- Don't let unbelief keep you paralysed when mustard seed faith can make you powerful.
- Don't settle for talking about mountains when God wants you to talk to mountains.
- Don't accept the impossible when nothing has to be impossible for you.
The mountain-moving faith Jesus offers isn't based on the size of your faith but on the size of your God. And your God is big enough, powerful enough, loving enough, and faithful enough to move any mountain you face.
Final prayer
Would you bow your heads with me as we pray?
Father, we confess that we have often been paralysed by unbelief rather than empowered by faith. We have focused on the size of our mountains instead of the size of our God. Today, we choose to plant seeds of mustard-seed faith. We choose to speak to our mountains rather than just talk about them. We choose to believe that nothing is impossible with You. Move in our lives, Lord. Move through our faith. Move our mountains. In Jesus' mighty name, Amen.
Church, go this week knowing that the God who moved mountains in the past is ready to move mountains in your present. Trust Him. Speak to your mountains. And watch Him do the impossible in and through your life.
Thank you for your time.
