The Meaning of Matthew 17:20: “If You Have Faith as a Mustard Seed”
Jesus Christ likened faith to a tiny seed. What lessons does He want us to learn from His comparing faith with a mustard seed?

What does Matthew 17:20 say?
“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.’”
At a teachable moment when His disciples were unable to cast out a demon from a child, He shared one of those analogies. First, the child was brought to Christ. He quickly rebuked the demon, and it immediately left (Matthew 17:14-18).
Afterward, the disciples asked Him why they hadn’t been able to help. Jesus answered that it was due to their unbelief.
He then told the disciples: “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” (verse 20).
Why did Jesus compare faith to a mustard seed? What can we learn from this analogy today?
Lessons from Jesus’ mustard seed analogy
A very little seed. A mustard is tiny, roughly the size of an average freckle on your skin.
Lesson 1: Faith is powerful
A mustard seed was one of the smallest seeds in the area where Christ lived, roughly the size of an average freckle on your skin!
An important lesson Jesus was teaching was that even the tiniest amount of faith has the power to move mountains!
In Luke 17:6, Christ also said that a mustard seed of faith can even uproot trees.
Of course, it isn’t us or faith itself that has the power to do that—but the almighty God we have faith in.
Yet one may ask, “When would I ever need to move a mountain or uproot a tree?”
Faith in God can remove our problems in life
God certainly has the power to move mountains (after all, He created them). Jesus, however, was using mountains as an analogy for life’s challenges—the seemingly insurmountable obstacles that prevent forward movement.
Jesus used mountains as an analogy for life’s challenges—the seemingly insurmountable obstacles that prevent forward movement.
Is there an obstacle in your life that needs to be removed? Is there something stopping you from growing spiritually?
Christ encouraged us by saying that God would help us remove the obstacle with even a minuscule amount of faith.
Consider a tree and its roots. Likewise, are there deep-rooted issues that need to be uprooted from our lives?
Maybe it’s smoking, drinking too much or some other addiction. Or perhaps it’s an issue with using coarse language or focusing on the faults of others.
Christ says that if we have even a tiny amount of faith in God, He can uproot those problems.
To learn more, read “Faith to Move Mountains? What Is the Meaning of Mark 11:23-24?”
We must believe in God’s power
Faith is about developing a deep belief in God and His limitless power.
The Gospels record a powerful example of a woman who had suffered from a blood issue for 12 years. It was so severe that doctors had been unable to help her at all. Yet she had heard about the miracles that Christ had done. She believed that if she could just touch His garments, she would be healed (Mark 5:25-28).
This woman believed in the power of God.
So she went out looking for Jesus, and upon touching His garment, she was healed immediately (verse 29).
This woman had a “mustard seed” of faith. Her faith was not yet strong and mature because she still had fear and hadn’t yet committed herself to be His disciple (verses 30-33).
Yet Christ still encouraged her. He told her that her faith in God removed the mountain of a problem in her life and uprooted the burden that followed her wherever she went.
It’s important to note that Christ did not say it was her “strong faith” that made her well, but simply “her faith.”
Belief in the power of God does not necessarily have to be mature and strong for God to intervene in our lives. He understands that this level of faith is developed only over time. Christianity is a growth process—not a one-time event.
But it has to start with faith—even if it’s tiny and limited.
Lesson 2: Faith starts small
An important lesson from this example is that this woman heard about Jesus’ miracles and acted (verse 27). This is where her faith started. Paul tells us, “Faith comes by hearing, and hearing by the word of God” (Romans 10:17). She heard what Christ did, believed He could do it for her and acted on that belief.
It is one thing to believe something, but it is another to act on it. And this is what God requires—He wants us to demonstrate our belief by our actions (James 2:17-18).
Now, our belief may be small at first. But remember Christ’s words that even a mustard seed of faith can result in God’s intervention in our lives.
It is one thing to believe something, but it is another to act on it. This is what God requires—He wants us to demonstrate our belief by our actions.
Many of Christ’s miracles were for individuals with only a mustard seed of faith. He didn’t limit His healing to only the disciples who had committed their lives to Him.
Christ even told one father who asked Him to heal his son that all things were possible if he believed in God’s power. The father then cried out, “Lord, I believe; help my unbelief!” (Mark 9:23-24). (For more insight, read “Help My Unbelief.”)
Christ did not tell the father that He could not heal his son because his faith was not yet strong enough. Instead, Christ performed a miracle because of the belief that was there.
This father’s mustard seed of faith should encourage us that God looks at our belief in His power, even if that belief is still in its earliest stages of development.
Unfortunately, many people in Nazareth had less than a mustard seed of faith—they had zero faith. Because of that, “He did not do many mighty works there because of their unbelief” (Matthew 13:58).
Yes, we must have some level, even if very small, of belief in God’s power for miracles to happen (Hebrews 11:6).
From seed to plant. A mustard seed can grow rapidly into a large shrub up to 25 to 30 feet tall.
Lesson 3: Faith grows
Even though a small amount of faith can bring powerful results, God doesn’t want our faith to stay the size of a mustard seed. He wants our faith to grow.
One characteristic of a mustard seed is that it grows rapidly into a large shrub up to 25 to 30 feet tall. That’s quite a change from a tiny seed!
Likewise, even though our faith starts small, it must continue to grow.
When the disciples asked Christ why they could not cast out the demon, He told them it was because of their unbelief (Matthew 17:20). Even though miracles can happen with a small amount of faith, some things, like casting out demons, require a different level of faith.
Jesus told His disciples that faith at that level requires being very close to God, which comes only through regular prayer and fasting (verse 21).
There are different degrees of faith.
To learn more about growing in faith, read “How to Grow in Faith.”
Strong faith takes time to develop
A relationship of complete trust between two individuals does not happen overnight. It takes months or even years to get to know someone and trust that we can depend entirely on him or her. The same is true in building a close relationship with God.
Strong faith in God usually develops after months or years of learning about God and experiencing His faithfulness and concern.
The more we understand God, His will and His unlimited power, the stronger our faith will grow. As we grow in understanding, our actions will more strongly reflect our confidence in God and His promises.
The Bible calls this living faith.
When Jesus told His disciples that faith could move mountains and that “nothing will be impossible for you,” He did not mean that having faith in God would enable them to do anything they wanted.
Instead, He was saying that faith in God would make it impossible for any obstacle to hinder them because of God’s ability to do what is humanly impossible (Matthew 17:20; 19:26).
By developing a close relationship with God, we can have the faith necessary to deal with any spiritual mountains that would be too big for us to overcome on our own.
Those with growing and living faith know that God may choose not to remove an obstacle in their life, but they trust that God will give them the strength to deal with and overcome it. Even if He doesn’t remove all the mountains in our life, He still promises to be with us as we face them (1 Corinthians 10:13).
Jesus Himself left us a powerful example of His complete trust in the Father, even when the Father chose not to remove the mountain before Him. The night before His horrific death, Jesus asked the Father if there could be a different way for Him to fulfill His mission. He prayed earnestly for the Father to do things differently, but still had complete trust by praying, “not My will, but Yours, be done” (Luke 22:41-44).
Jesus left us a powerful example by faithfully yielding to His Father’s will.
To learn more about developing living faith, read “What Is Living Faith?”
Learn the lesson of the mustard seed: Grow in faith
Yes, faith starts small. But as Christ said, even a mustard seed of faith can accomplish much.
Consider that if God acted according to our will every time we asked for something, our faith would not grow. If He did, our faith would be based entirely on what we see. In that case, our trust in God’s will and wisdom would never develop.
Instead, God wants us to “walk by faith, not by sight” (2 Corinthians 5:7).
Like a mustard seed, this level of regular and daily faithfulness takes time to grow. But grow, we must!
By building a close relationship with God, we can and will grow in faith, and not be hindered or discouraged by any mountains that get in our way.
Photo credits:
iStock.com/skhoward
iStock.com/Meenakshi Vashistha
iStock.com/Marinela Malcheva
Date Posted: January 13, 2025