“If you have faith the size of a mustard seed, you would say to (this) mulberry tree, ‘Be uprooted and planted in the sea,’ and it would obey you. (Luke 17) One might expect Jesus to well receive the request for more faith, but the response seems to imply that the disciples do not (yet) understand the real nature of faith. The saying is grammatically complex in Greek.  The first part of verse 6 is a construct that implies the disciples do have faith, but the second part of the verse contradicts that positive assessment with the implication that the disciples have not yet scratched the surface of the real nature of faith.

The disciples assume that they have faith and they will need more to accomplish what Jesus has taught in vv.1-5.  Jesus seems to be saying they don’t even have faith is the smallest quantity (hence the reference to the mustard seed). The point is not that they need more faith, but that they need to understand that faith allows God to work in a person’s life in ways that defy ordinary human experience.  This saying is not about performing extraordinary miracles, but that with even the smallest of faith, God can help them to live by his teachings on discipleship.

[Note: other commentaries suggest that Jesus is affirming their faith – in other words, they do not need more. If they believe and act on the faith that they already have, then they can rebuke and repent and forgive within the community. In essence, he seems to imply that they don’t need more faith, but to make use of the faith that they already have.  Why the difference?  It depends on how one assesses the conditional primary and secondary clauses present in the verse.]

Image credit: The Exhortation to the Apostles | James Tissot | ca. 1890 | Brooklyn Museum NYC | PD-US