The disciples’ demand (not a request) that Jesus increase their faith, (Lk. 17: 5) with a hint of desperation that such a demand entails, seems to come out of nowhere when it begins the Gospel reading. So let us look at the preceding paragraph for some context.
That paragraph begins with Jesus’ ominous warning against being occasions of stumbling (scandals) for any of Jesus’ “little ones.” Unlike the parallels in the other synoptic Gospels, however, this warning is quickly followed by an admonition to rebuke those who cause stumbling but then to forgive them if they are penitent, even if it is seven times a day, which is a lot of forgiving.
So, the disciples aren’t having a problem believing in the Nicene Creed. They are having a problem accepting this demand to be forgiving on such an incredible scale. After all, if one repents seven times a day, how serious is the repentance? Forgiving like that often requires the patience of a saint and not even many of the saints I know anything about are as patient as that. The “faith” at issue here, then, seems best understood in the usual meaning in Jesus’ time which would stress fidelity to Jesus’ teachings and trust in his sanity in the face of such impossible demands. In the same fashion, we can understand “faith” as used in Habakkuk 2:4 as referring to remaining steadfast to Yahweh in the face of the human violence of social injustice in Israel and the violence of the Babylonian invaders. That is, in the face of people who cause much stumbling and need forgiveness almost nonstop.
Unlike the parallels in Matthew and Mark, faith the size of a mustard seed is enough to move this mountain, perhaps the Temple Mount and its sacrificial system, from here to there. But mulberry trees have nothing to do with sacrifice. So why a mulberry tree in this version? A mulberry tree can be nice to have around but it an be a nuisance in some circumstances. When I was growing up, we had a mulberry tree on the edge of our property. The berries were a nice treat but they also stained the driveway a deep purple. Mulberry trees also have complex root systems that spread out a large distance just under the surface and they also send sinker roots deep into the soil. This may be one of the reasons my father used a tree removal service rather than faith to move the tree off from the property.
We an see the mulberry tree as an image of the intractability of the occasions for stumbling that we encounter on a daily basis. The image also stands for the tangle of our anger and frustration over being asked to forgive those who keep making us stumble over and over again. The close coupling of Jesus’ admonitions here suggests that all of us cause others to stumble about as much as we have occasion to forgive others for making us stumble. Faith the size of a mustard seed is enough to pull us out this tangle of scandal and stumbling and yet we have trouble having as much faith as that!
A brief parable follows. We are apt to think the master treating his slaves so harshly stands for God, but Jesus is asking: Whom among you would say to his slave to come sit down for dinner after a hard days’s work? The implication is that we are the ones who would like to have the power to order people about like that. But is that faithfulness to Christ? Looks more like a cause of stumbling to me. Jesus then shifts to the perspective of the slave who must not presume to be worthy of any reward, just as slaves were so considered in his time. In a similar parable in Luke 12, Jesus says that the master is the one who will wait on those slaves who eagerly await his return. In daily life, we often feel that we are slaves of those who cause trouble and so demand much attention and energy on our part and yet are the last to express any gratitude for what we do for them. We tend to resent such slavery and take refuge in vengeful anger and maybe some grudging forgiveness that makes us feel superior. But Jesus places himself in the position of the slave to those who stumble and makes others stumble, so that is where we will find Jesus if we have the faith the size of a mustard seed.