“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.” (Mt 17:20 ESV)
I always thought it completely illogical that intangible faith could be made measurable by human weights and dimensions. Faith has no mass or matter. But in actuality, Jesus does not say, ‘faith in the quantity of a mustard seed,’ but rather “faith like a mustard seed.” In literature, the construction “x like y” and “… as …” are known as simile, that is, a comparison metaphor.
Jesus also used a mustard seed simile for the Kingdom of Heaven, explaining that mustard is “the smallest of all seeds, but when it has grown, it is larger than all the garden plants and becomes a tree.” (Mt 13:31-32; Mk 4:30-32; Lk 13:18-19). Jesus seems to be saying that faith does not just exist or suddenly manifest; faith starts invisibly small and grows over time. When this faith is mature, it draws to it those who need its shelter. Incidentally, that was how Jesus grew his faith, incrementally, slow and steady. When his faith was full, those in need sought his presence as a shelter from their afflictions.
The adjacent passage tells of an epileptic boy whom the disciples could not heal. Jesus later tells the disciples that they were unsuccessful because “this kind never comes out except by prayer and fasting” (Mt 17:20-21).
This statement will strike the attentive reader as bizarre became Jesus did not press pause on the situation to fast and pray. So how can prayer and fasting be the formula of such authority? Yet this was precisely how Jesus laid his foundation when he was driven by the spirit into the wilderness after his baptism. So perhaps Jesus is saying to them, ‘you haven’t grown your faith enough to be at the place where I am because you haven’t done the things that I did (and do) to grow my faith.’ Alternately, Jesus is saying, “this kind [of faith] never comes [forth] except by [private] prayer and fasting.” I’m not merely taking liberties with the text. If the disciples did not grasp what Jesus said, how could they be expected to capture his nuance? (see Jn 16:29)
Peter, James, and John likely came to understand this better than the other disciples by the time of Jesus’ betrayal in the Garden. These three witnessed Jesus’ transfiguration (Mt 17:11) and comprised Jesus’ advanced prayer group where they were expected “watch” and “pray” with him (Mt 26:37). Jesus noted that their spirits desired to lay hold of advanced faith, but their bodies were immature.
Is it mere coincidence that Jesus spoke of a “garden” when explaining the mustard seed similes? Perhaps it was meant to be a clue to connect he dots. Extreme miracles come from mature faith, a faith that has been cultivated. Mountain-moving, life-saving, world-changing faith does not just manifest. Are we willing to press into God with extreme private prayer and fasting in order to walk publically in his power? Are we willing to eliminate all the distractions of social and broadcast media and re-allocate that time to private communion with God Almighty until physical needs become detestable to us? Is our private communion with God so intense that we can’t bear to tear ourselves away for food, that we refuse to sleep so that we my linger in Shekinah? That is the kind of prayer and fasting of which Jesus spoke. It’s a lifestyle of desperate spiritual hunger and thirst, not a checklist to charge our batteries in case we need to flex our faith. Mustard-seed faith describes a process, not a quantity.