A Prosthetic Faith I (Lk 17:5-10)

"The apostles said to the Lord, “Increase our faith!” 6 The Lord replied, “If you had faith the size of a mustard seed, you could say to this mulberry tree, ‘Be uprooted and planted in the sea,’ and it would obey you. 7 “Who among you would say to your slave who has just come in from plowing or tending sheep in the field, ‘Come here at once and take your place at the table’? 8 Would you not rather say to him, ‘Prepare supper for me, put on your apron and serve me while I eat and drink; later you may eat and drink’? 9 Do you thank the slave for doing what was commanded? 10 So you also, when you have done all that you were ordered to do, say, ‘We are worthless slaves; we have done only what we ought to have done!’”

I. Introduction

The title of this exposition is taken from a Greek word in v. 5. The disciples came to Jesus and said, "Increase our faith." The first word in Greek is in the imperative mood (command) and is derived from prostithemi, which means "to add, increase." The actual word is prosthes, from which we derive our words prosthesis, prosthetic, etc. These words usually find their home in a medical context in our world and refer specifically to the replacement of a "defective or absent" body part by "artificial substitutes" (OED).

But I will be taking the word prosthetic out of the medical context and using it theologically. Indeed, why should the medical profession have all the good words!? I am only doing this because the disciples in Luke 17:5 use the word. "Increase our faith" is, in Greek, "prosthes emin pistin." Maybe this will be the first of our efforts to reconquer the English language from the doctors, to find humanistic or theological meaning in the words we use.

Indeed, the original use of the word prosthesis in English was in the grammatical, and not medical, context. It goes back to 1550 and means "the addition of a letter or syllable to the beginning of a word." It stands in contrast to aphaeresis (look that up!). An example coming from T. Wilson's 1553 Arte of Rhetorique is homey: "He did all this to berattle hym." The addition of "be" at the beginning to intensify a word is an example of the grammatical use of prosthesis.

If you are still reading this essay, however, you are probably doing so to get an exposition of the text. Now I turn to that, under three heads: (1) Faith--from Little to Big; (2) Faith--from Faith to Faithfulness; (3) Faith--which Never Quits. Let's turn to each of these now.

II. Faith--From Little to Big (17:5-6)

Faith is on Jesus' and the disciples' minds as this passage opens. Jesus has just finished exhorting them (vv. 1-4) to beware about causing "little ones" to stumble, i.e., to do things that cause others to weaken in or lose faith. The disciples probably think that their faith is insufficient for the task, and so they naturally ask Jesus to "increase" it for them. What they don't realize is that posing questions to Jesus or making observations that bring forth his response is often, in Luke's Gospel, a way for Jesus to intensify the demands of discipleship. That is, in the Gospels in general there is no such thing as an "innocent" question or request. Each question/request is taken by Jesus as an opportunity to bring the interlocutor into deeper understanding of and commitment to the faithful life.

For example, Peter asks a seemingly "innocent" question in 12:41--whether Jesus intends a parable for them. In response Jesus intensifies the parable, emphasizing the need for focused discipleship while waiting for the Master to return from a long journey. Thus, when the disciples make a request here, the author is giving careful readers a subtle signal that something from Jesus that will increase the demands of discipleship is on the way (see another example in 21:7ff.). Maybe after you know this, this will affect how many questions we ask of God.

The particular request here is understandable. "Increase our faith" or, in my (cute?) title, "Give us a prosthetic faith." The disciples want more faith to cope with the warning of Jesus in 17:1-4. They want faith to go from "little" to "big." In response, Jesus gives them a visual image of "little" and "big." If they had faith as a seed of mustard (among the smallest of things), people could say to the mighty sycamore, "Be you uprooted and replanted."

It is hard to know always exactly what modern herb or tree is indicated by an ancient word. But other ancient authors speak about the mustard as among the smallest of all herbs, and the Greek word which the NRSV translates "mulberry" is, in fact, sykamin, itself derived from the Hebrew, and translated by many scholars as "sycamore." For any of you who know or love trees, we have three major kinds of sycamore trees today--Platanus x acerifolia (London Plane Tree); Platanus racemosa (California Sycamore) and Platanus occidentalis (American Sycamore). The acerifolia casts the most tremendous shadow you have ever seen from any tree, except perhaps from a European Beech (Fagus sylvatica), which was not a tree known in the Holy Land at the time. Thus, Jesus is going "from small to big" in giving us his answer. Faith is something that "moves mountains," or that can move the sycamore tree.

Note that Jesus doesn't just say "uproot" the big tree. He says "uproot and replant." Faith is something that isn't like a stunt car in an action movie--where dozens of cars or buildings are sacrificed in order to satiate the lust of theater-goers for destruction of expensive things. Faith may uproot, but it also replants. I don't know if sycamores can live in the water, but many trees can, and many trees find their homes there (such as the bald cypress--Taxodium distichum).

Let's pause on that image for a moment before moving on. Increase in faith will uproot things. That itself is an interesting concept. Faith doesn't just confirm, calm, and comfort. Faith is the prelude for action and for change.

But there is something else going on here, too, something that fits perfectly with our 21st century world, and that is that the most powerful sources of life are now considered to be the smallest things in the universe. We are in a time of unparalleled discovery in microbiology and allied fields. As I mentioned here, Prof. E. O. Wilson of Harvard estimates that we have only discovered or identified approximately 1-5% of living things in our universe. Most of the other 95-99% are microscopic organisms, viruses, bacteria, slimes, fungi and things living in the sea that we simply haven't had the technology or finances to understand until recently. The future of "big life" (i.e., our life) is in "little life." Every time, then, that I think of Jesus' words which commend faith even as small as a mustard seed, I think of the exciting and propitious work of microbiologists.

The next essay finishes my thoughts.

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