And Jesus said to them, Because of your unbelief: for truly I say to you, If you have faith as a grain of mustard seed, you shall say to this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible to you.
Because.
Matthew 17:17 Then Jesus answered and said, O faithless and perverse generation, how long shall I be with you? how long shall I suffer you? bring him hither to me.
Matthew 14:30,31 But when he saw the wind boisterous, he was afraid; and beginning to sink, he cried, saying, Lord, save me…
Hebrews 3:19 So we see that they could not enter in because of unbelief.
If.
Matthew 21:21 Jesus answered and said unto them, Verily I say unto you, If ye have faith, and doubt not, ye shall not only do this which is done to the fig tree, but also if ye shall say unto this mountain, Be thou removed, and be thou cast into the sea; it shall be done.
Mark 11:23 For verily I say unto you, That whosoever shall say unto this mountain, Be thou removed, and be thou cast into the sea; and shall not doubt in his heart, but shall believe that those things which he saith shall come to pass; he shall have whatsoever he saith.
Luke 17:6 And the Lord said, If ye had faith as a grain of mustard seed, ye might say unto this sycamine tree, Be thou plucked up by the root, and be thou planted in the sea; and it should obey you.
faith.
a grain.
Matthew 13:31 Another parable put he forth unto them, saying, The kingdom of heaven is like to a grain of mustard seed, which a man took, and sowed in his field:
Mark 4:31 It is like a grain of mustard seed, which, when it is sown in the earth, is less than all the seeds that be in the earth:
nothing.
Mark 9:23 Jesus said unto him, If thou canst believe, all things are possible to him that believeth.
Luke 1:37 For with God nothing shall be impossible.
Luke 18:27 And he said, The things which are impossible with men are possible with God.
For truly I tell you,
This phrase underscores the authority and truthfulness of Jesus' words. It is a common expression used by Jesus to emphasize the importance and certainty of His teachings. The use of "truly" (or "verily" in some translations) is a solemn affirmation, indicating that what follows is a foundational truth for the disciples and all believers.
if you have faith the size of a mustard seed,
The mustard seed is one of the smallest seeds known in the region, symbolizing something very small yet potent. Jesus uses this metaphor to illustrate that even a small amount of genuine faith can have great power. This imagery is consistent with other teachings of Jesus, such as the parable of the mustard seed in Matthew 13:31-32, where the kingdom of heaven is likened to a mustard seed that grows into a large tree.
you can say to this mountain, ‘Move from here to there,’ and it will move.
Mountains often symbolize insurmountable obstacles or challenges. Jesus uses hyperbolic language to convey that faith can overcome great difficulties. The specific mention of "this mountain" may refer to the Mount of Transfiguration or another nearby mountain, emphasizing the tangible reality of faith's power. This teaching is echoed in 1 Corinthians 13:2, where Paul speaks of faith that can move mountains, highlighting the transformative potential of faith in action.
Nothing will be impossible for you.
This statement reinforces the limitless possibilities available through faith in God. It aligns with other biblical promises, such as Philippians 4:13, which declares that believers can do all things through Christ who strengthens them. The emphasis is on God's power working through the believer's faith, rather than human ability alone. This assurance encourages believers to trust in God's sovereignty and power, even in seemingly impossible situations.
Jesus speaks these words immediately after the disciples fail to cast a demon out of a boy (Matthew 17:14-19). Their problem is not lack of technique but lack of trust in God’s power.
• Similar rebukes appear in Matthew 6:30 and 14:31, reminding us that even believers can lapse into “little faith.”
• Hebrews 11:6 states, “Without faith it is impossible to please God,” underscoring that faith is the indispensable channel through which God’s power flows.
• The verse shows that ineffective ministry often traces back to unbelief, not to God’s unwillingness.
This phrase (amen legō hymin) signals Jesus’ absolute authority. He is not offering a suggestion but a divine guarantee.
• Matthew 5:18 (“Truly I tell you, until heaven and earth pass away…”) and John 14:6 reveal the same authoritative tone—when Jesus says “truly,” heaven backs His promise.
• Because Scripture is accurate and literal, we can rely on every promise that follows.
A mustard seed is one of the tiniest seeds (cf. Matthew 13:31-32), yet it contains life and growth potential.
• Jesus highlights that genuine faith—even when seemingly small—connects us to God’s limitless power.
• Luke 17:6 repeats this image, reinforcing that effectiveness is not about the believer’s greatness but the greatness of the God in whom we trust.
• The point is quality, not quantity: authentic dependence on God counts more than impressive displays of self-confidence.
Jesus selects a mountain—immovable in human terms—to illustrate what divine power can do through believing prayer.
• Mark 11:23 cites the same promise, tied directly to prayer that does not doubt.
• Zechariah 4:7 pictures a great mountain becoming level ground before God’s servant, showing continuity between Old and New Testament demonstrations of God’s might.
• While mountains can symbolize daunting obstacles, the statement also affirms God’s literal capability; nothing in creation outranks the Creator.
The scope widens from a single mountain to “nothing.” This promise assumes alignment with God’s will; faith never manipulates God but cooperates with Him.
• Matthew 19:26 says, “With God all things are possible,” anchoring possibility in God’s nature.
• Philippians 4:13 echoes, “I can do all things through Christ who gives me strength,” showing that the believer’s power is derivative, not inherent.
• John 15:7 balances the promise: “If you remain in Me and My words remain in you, ask whatever you wish, and it will be done for you.” Faith-filled requests flow from abiding fellowship with Christ.
Matthew 17:20 teaches that even a small, genuine faith unlocks God’s limitless power. Jesus rebukes unbelief, affirms His authority, and assures His followers that dependence on Him can topple the seemingly immovable. When our trust rests in the living God, no obstacle stands a chance, for with Him nothing is impossible.
(20) Because of your unbelief.--The various reading, "Because of your little faith," found in many, but not the most authoritative MSS., is interesting as an example of a tendency to tone down the apparent severity of our Lord's words. They show conclusively that the disciples themselves came under the range of His rebuke to the "faithless and perverse generation."If ye have faith as a grain of mustard seed.--The hyperbolical form of our Lord's words, repeated afterwards in Matthew 21:21, excluded from the thoughts of the disciples, as from our own, the possibility of a literal interpretation. The "grain of mustard seed" was, as in Matthew 13:31, the proverbial type of the infinitely little. To "remove mountains" was, as we see in 1Corinthians 13:2 (this may, however, have been an echo of our Lord's teaching), the proverbial type of overcoming difficulties that seemed insurmountable. The words were, we may believe, dramatised by a gesture pointing to the mountain from which our Lord and the three disciples had descended, as afterwards by a like act in reference to the Mount of Olives (Matthew 21:21).
Nothing shall be impossible unto you.--The words, absolute as they sound, are yet, ipso facto, conditional. Nothing that comes within the range of faith in the wisdom and love of God, and therefore of submission to His will, is beyond the range of prayer.
Verse 20. - Because of your unbelief. The Revised Version adopts the reading, little faith, in accordance with the best authorities; but it looks like a softening of the original term "unbelief," which corresponds better with Christ's own censure, "faithless generation." Jesus gives two reasons for the apostles' failure, one connected with their own moral condition, and one (ver. 21) derived from the nature of the demons exorcised. They had, indeed, shown some faith by making even the attempt at the expulsion of the devil, and were not to be classed with the unbelieving scribes; but they had acted in a half-hearted manner, and had not displayed that perfect confidence and trust which alone can win success and make all things possible. Verily I say unto you. The Lord proceeds to give that lesson concerning perfect faith and its results, which he afterwards repeated in connection with the withered fig tree (Matthew 21:21, where see note) and elsewhere (Luke 17:6). If ye have faith as a grain of mustard seed, which, as he says (Matthew 13:32), "is less than all seeds." He means a faith real and trustful, though it be small and weak. The phrase is proverbial, expressive of littleness and insignificance. The mustard seed is quite little, but, grown in favourable soil and under sunny skies, it becomes, as it were, a tree among herbs, so that birds may nestle in its branches. To it faith is compared, because, small at first, it contains within itself power of large development and increase; from minute grains copious results are produced. Ye shall say unto this mountain. He points to the hill of Hermon, where the Transfiguration had taken place. Remove hence. It is usual to consider the expression here as an Eastern hyperbole, not to be taken literally, but meaning merely that the greatest difficulties may be overcome by faith. This may be true, but it seems hardly adequate to the explanation of our Lord's emphatic words. St. Paul writes in a similar strain (1 Corinthians 13:2), "If I have all faith, so that I could remove mountains;" where there is nothing necessarily hyperbolical in the supposition. It seems rather that Jesus meant his words to be received literally, implying that if such a removal as he mentioned was ever expedient and in accordance with God's will, it would be effected by the power of faith; not that he hereby sanctioned an arbitrary and wanton display of miraculous power, but he gives an assurance that, were such a measure rendered necessary for the cause of religion, it would be performable at the call of one whose whole trust was centred on God, and whose will was one with God's will. Mediaeval writers, followed by later Roman Catholic commentators, give instances of such stupendous effects of faith. The evidence of such miracles is, of course, defective, and would not satisfy modern criticism, but the existence of such legends proves that a literal view was taken of our Lord's saying. Nothing shall be impossible unto you. The man of faith is practically omnipotent; moral and material difficulties vanish before him.