Luke 17:6Meaning & Commentary from the Church Fathers

He mentions the mustard seed, because, though small in size, it is mightier in power than all the others. He implies then that the least part of faith can do great things. But though the Apostles did not transplant the mulberry tree, do not thou accuse them; for our Lord said not, You shall transplant, but, You shall be able to transplant. But they did not, because there was no need, seeing that they did greater things. (Hom. 32 in 1 ad Cor. c. 13:2.). But some one will ask, How does Christ say, that it is the least part of faith which can transplant a mulberry tree or a mountain, whereas Paul says that it is all faith which moves mountains?

The disciples hearing our Lord discoursing of certain arduous duties, such as poverty, and avoiding offences, entreat Him to increase their faith, that so they might be able to follow poverty, (for nothing so prompts to a life of poverty as faith and hope in the Lord,) and through faith to guard against giving offences. Therefore it is said, And the Apostles said unto the Lord, Increase our faith.

The Lord demonstrates that the establishment of faith is a significant and unique gift by stating, "If thou hadst faith as a grain of mustard seed, thou couldst say to the sycamine tree, ‘Uproot thee in the sea,' and it would obey thee." This highlights that those who place their trust in Christ do not lean on their own abilities; rather, they acknowledge His authority to achieve all things. It is through Him that all good is accomplished in the hearts of people, yet they must prepare themselves to be recipients of this profound grace. If faith has the power to dislodge what is deeply rooted in the earth, one can assert that nothing is so unyielding that faith cannot move it, should that removal be essential.

We may indeed understand that they asked for the increase of that faith by which men believe in the things which they see not; but there is further signified a faith in things, whereby not with the words only, but the things themselves present, we believe. And this shall be, when the Wisdom of God, by whom all things were made, shall reveal Himself openly to His saints face to face.

Or this is said because faith keeps out the unclean spirit, especially since the nature of the tree falls in with this meaning. For the fruit of the mulberry is at first white in the blossom, and being formed from thence grows red, and blackens as it gets ripe. The devil also having by transgression fallen from the white flower of the angelic nature and the bright beams of his power, grows terrible in the black odour of sin.

faith comparable to a mustard seed. If your faith were as intense, robust, and fervent as a mustard seed, which is its defining quality, you would be able to uproot trees and plant them in the sea. In making this statement, He commended unwavering faith and illustrated its immense potential. He also referred to faith and the mustard seed in the thirty-fifth chapter of the Gospel of Matthew, although in a different context.

That is, that the faith which has already been received in its beginning, might go on increasing more and more unto perfection.

Or our Lord here compares perfect faith to a grain of mustard seed, because it is lowly in appearance, but fervid in heart. But mystically by the mulberry tree, (whose fruit and branches are red with a blood-red colour,) is represented the Gospel of the cross, which, through the faith of the Apostles being uprooted by the word of preaching from the Jewish nation, in which it was kept as it were in the lineal stock, was removed and planted in the sea of the Gentiles.

There exists a singular faith—the Orthodox faith—which encompasses the correct beliefs about God and His creations, both spiritual and material, as bestowed upon us by the Holy Universal Church through divine grace. In contrast, there is the faith of insight, characterized by knowledge, which does not negate but rather strengthens the faith from which it stems. The initial faith is imparted to us through Holy Baptism, granted by Christ’s grace, rather than through our own deeds, such as observing commandments and enduring trials. Conversely, the profound faith of insight develops within us following our inner transformation. Regarding this faith of insight, the Lord proclaimed, 'If only ye had faith as a grain of mustard seed.'

The Lord responded to them, stating, "If you had faith as small as a mustard seed, you could say to this sycamore tree, 'Be uprooted and planted in the sea,' and it would obey you" (Luke 17:6). This illustrates that when faith ignites, much like a mustard seed, even the most challenging situations become bearable for the believer, and what seems unattainable becomes achievable, leading to miraculous occurrences. Faith flourishes when we are free from doubts and steadfast in its teachings.

The apostles, recognizing their need, implored for an increase in faith to empower them in their commitment to observe His commandments diligently. The Lord, pleased with their request and eager to enhance their fervor, reiterated His earlier teaching on the strength of faith in concise terms. While doing so, He cautioned against the arrogance of the Pharisees, emphasizing that despite their adherence to the law, they ought never to view themselves as anything more than servants of the unchanging God.

What Jesus communicates to all His disciples in this passage is a condensed version of what He had previously conveyed to the apostles. The Lord revisits the caution against temptations and the imperative to forgive a brother who sins, likely because He was in the presence of Pharisees and tax collectors. The Pharisees presented themselves as knowledgeable leaders in the truth, and their actions might lead others astray in various ways, such as their perspective on Christ’s teaching regarding avarice, as well as their disdain for tax collectors and sinners.

The Apostles received authority from Jesus to perform miracles in His name, yet to do so, unwavering faith in the divine power of the One who bestowed this authority was essential. They needed to be confident that miracles could indeed occur through this power. However, as the Apostles sometimes lacked such faith, it became necessary to demonstrate to them that exercising their authority required a stronger faith. Their shortcomings were not mere coincidences; instead, they served to encourage and bolster their faith.

In the event following the Transfiguration, Jesus Christ had already granted His disciples the authority to expel demons before this moment, and at times, even individuals who were not among His closest followers acted on His behalf (Mark 9:38). They did not fail in their efforts. Consequently, the disciples seized the first chance to inquire about the reasons behind their recent inability to succeed. Jesus candidly explained that their lack of faith was the reason. It is possible that His absence had diminished their trust, or they may have felt less equipped to face challenges without Peter and the sons of Zebedee by their side. Additionally, the tragic news of their Master's rejection and impending death may have weighed heavily on the minds of the most vulnerable among them.

"If you had," etc.: refer to the commentary on Matthew 17:20. The Lord does not deny the existence of faith within His disciples' hearts, yet He illustrates how their current level of faith differed significantly from the fuller measure they would eventually receive and inhabit. - "To this fig-tree": the Lord likely indicated a nearby fig-tree. - "Would have obeyed": the tree is depicted as living and aware; it would have responded to the apostles' command had they possessed the requisite measure of faith.

The Lord, while cautioning His disciples about the perils of temptation and the importance of forgiving others, provided them with vital guidance. As they remained in His presence and absorbed His teachings, they became increasingly aware of their shortcomings in living out His commandments. Even after having followed Christ and being blessed with the ability to perform miracles, they struggled to break free from worldly desires and expectations. At times, they found it difficult to grasp the teachings of their heavenly Master (Matt. 16:7), which left them feeling that their faith was not at the level it should be amidst their witness of the Word of Life (1 John 1:1).