Sheep can do nothing for the shepherd. They cannot carry him when he's weary, heal him when he's hurt, guide him to water or pasture... It is the shepherd who does everything for the sheep.
In ancient times, sheep were a measure of a person's wealth. They were valuable animals that produced wool, mutton, and milk. The wool was by far the most valued production and was, of course renewable.
It was the wool that really struck me in the conference lessons. That is the most valuable production of the sheep: wool. Yet sheep do not consciously grow wool. They don't sit in the pasture and think, "I'm going to grow some wool today," then close their eyes and strain as they say, "Grow, wool! Grow!"
It's really the shepherd who has the most to do with the quality or quantity of the sheep's wool. If the sheep is well cared for and eats the good grass and drinks the clear water, wool is produced. All those things have to do with the Shepherd and how he cares for the sheep. If the shepherd brings the sheep to bad grasses, it will become malnourished. When it's malnourished, wool production is poor. The wool is shorter, thinner, brittle. And other areas of sheep production are not as good either. The milk is not as nutritious or as abundant. The lambs may be smaller, skinnier, fewer and weaker...
This analogy to Christian works could not be better. Readers occasionally write to thank me for being obedient to God's calling to write. The sentiment has always left me somewhat bemused, and now at last I have the proper metaphor to express why. It's like going into the field and thanking the sheep for making wool, when all the sheep did was follow the shepherd and eat what He provided. The wool was a side-product from the sheep's point of view. Better would be to thank the shepherd for taking such good care of the sheep. Or to thank the sheep for eating, but that seems a little weird, too, since what's so special about eating? Sheep are dumb, yes, but even they know how to eat!
Now, whenever I hear the term "bring glory to God" I visualize myself sprouting wool -- whatever production I have is something I do because I'm designed to do it. If I'm eating the right spiritual food and drinking the pure water, at rest and content, then it's going to happen. Not because of me and my intent and my plans, but because of my Shepherd's.