Our Gemara on Amud Beis discusses a halacha in muktzah, certain items which are forbidden to carry on Shabbos because of their lack of utility. One way to understand the prohibition of Muktzah is that Shabbos is a day of rest, and therefore long-term planning activities and construction are prohibited. Since they are practical needs, utensils that have immediate and daily use are permitted to carry; however, something that has no immediate use is not about the mindfulness of the moment and would signal engagement in construction, building and planning, which is not consistent with the restful meditative mode of Shabbos.
What about a vessel that broke on Shabbos? On one hand, it started the Shabbos with a utility, but now it has limited functionality. The Gemara rules that if the broken pieces still have some function, then they retain some utility and can still be carried. However, if they have no function at all, then they become like rocks or dirt and are forbidden. We see from here that though ordinarily a shard by itself does not have enough utility to be considered a utensil, if it came from a larger vessel it still has enough function to retain its utility and permissibility to carry on Shabbos.
Bnei Yissachar (Kislev and Teves 3) applied this idea on a mystical level. There is a tradition (Yevamos 97a) about how a Torah sage’s study continues beyond his death:
“With regard to any Torah scholar in whose name a matter of halacha is said in this world, his lips mouth the words in the grave, as though he is talking.”
Bnei Yissachar explains that ordinarily in order to fulfill a mitzvah, a physical bodily action is required. This is why one cannot perform mitzvos in the world to come because he is only soul and no body. Yet, when we study Torah taught to us by a sage, it is as if he is still talking, and he receives the reward as if he is physically performing the mitzvah. He compares this to our teaching regarding the broken shards. Even though ordinarily the shards would not have enough function to be considered a utensil, if they came from a larger utensil and still have some function, they are valid. So too, although the scholar’s body has deteriorated, if we are studying his teachings, then we are still using some of the leftover shards from his physical existence. As such, there is enough function that remains that it is as if he still is performing the mitzvah of Torah Study.
He says that the law of Chanuka lights has a similar idea. If one lit Chanuka lights with the proper amount of oil in a place where it had the potential to remain lit for the requisite amount of time, but suddenly by accident, a wind, or some other force extinguishes the lamp, there is no need to relight, and the mitzvah is still accomplished. In a spiritual sense, the lamp remains lit, even though it has been extinguished.
When mystics use metaphors, they don’t just mean them as metaphors. From the mystical mindset, the entire reality is a metaphorical representation of a deeper, Godly truth. If we see something in the Torah that tells us that part of a utensil retains its value and utility, that might be based on a material manifestation and law of physics, but that itself, because it comes from the wisdom and design of God, has a deeper validity and truth. So it’s not just a metaphor that the body of the sage lives on through the broken shards of his teachings, but it is actually that he is living on because he is a deeper representation of the paradigm that gets expressed in a limited physical way in the laws of muktzah. Stated in other words, the deeper spiritual truth is the reality, and the laws of muktzah are the metaphor.