After the death of their father, Jacob, his sons fear for their lives from their younger brother, Joseph. With his father no longer alive, there is nothing to stop Joseph, now the Grand Vizier of the Egyptian Kingdom, from killing them all. They have good reason to fear. Joseph had never explicitly forgiven them for selling him into slavery. And so they plead with him, feeding him a potentially fabricated request from their father to forgive their offense. Joseph replies that he can do them no harm because his sale into slavery was all part of a divine plan to save the world from famine. He consoles them and tells them that everything will be all right [Bereishit 50:21]: “‘And so, fear not. I will sustain you and your dependents.’ He reassured them, speaking kindly to them.”
How does Joseph “reassure” his brothers? Rashi brings two explanations. In his first explanation, Joseph tells his brothers that they have nothing to fear. “After all, what kind of person would kill his own brothers?” Excuse me? I can think of some examples: Cain, Yishmael, and Esau, just to name a few. Seeing as this answer would not likely reassure Joseph’s brothers, Rashi provides another explanation. Quoting from the Talmud in Tractate Megillah [16b], Rashi suggests that Joseph told his brothers, “Ten lamps could not extinguish one lamp. How can one lamp extinguish ten lamps?” Prima facie, this explanation is no better than his first explanation. Joseph seems to be telling his brothers, “While I’d like to take revenge, the odds are stacked against me, so you guys are safe for now.” Who is to stop Joseph from exacting revenge? He is the Prime Minister of Egypt. As the popular adage goes, “It’s good to be the king.” What kind of reassurance is this?
In this essay, we will zoom into Rashi’s second explanation. Other than the questions we raise above, the science just doesn’t make sense. One lamp can ignite another lamp, but how can it extinguish another lamp? Would it not have been more fitting for Joseph to tell his brothers, “Ten people could not extinguish one lamp. How can one person extinguish ten lamps?” A way ahead can be found in the dreams Joseph dreamt as a child, dreams that eventually resulted in his sale into slavery. The Torah explicitly describes two of these dreams. In Joseph’s first dream, he and his brothers are gathering wheat when his sheaf rises and his brothers’ sheaves bow down to it. In his second dream, the sun, the moon, and eleven stars all bow down to him. While the Torah describes only two dreams, some commentators suggest that there was a third. They point to the brothers’ response to Joseph’s first dream [Bereishit 37:8]: “They continued further to hate him on account of his dreams and on account of his words.” Notice that the word “dreams (chalomotav)” is in the plural, indicating that, at the time, he had already dreamt a dream that irritated his brothers. Based on this indication, the Riva suggests that Joseph did indeed dream another dream before the dream of the sheaves, but that its content remained unknown. The Riva then brings a second interpretation, suggesting that the Talmud in Tractate Megillah is really referring to Joseph’s first dream, in which his brothers’ lamps attempt unsuccessfully to extinguish his lamp. This innovation raises a question: If Joseph did really dream a third dream, why does the Torah wait until years later, after Jacob dies, to reveal its content?
In ancient Egypt, light was provided by oil lamps. Oil lamps are typically made of clay. They are squat with a low centre of gravity for increased stability, and they store liquid fuel, typically olive oil. A cotton wick is inserted into the oil and a small part of the wick remains outside the lamp. When the wick is lit, oil is drawn from the lamp into the wick via capillary force. The heat of the burning wick vaporizes some of the nearby oil, which reacts with the heat of the fire and the oxygen in the air in order to produce carbon dioxide, steam, heat and, of course, light. The amount of light produced by the lamp is increased by the burning of carbon particles present in the oil, causing them to glow and creating a small amount of soot that can be seen by holding a piece of paper above the fire.
Now that we understand the mechanism in which a lamp produces light, how would we go about extinguishing that lamp with another lamp? The Riva suggests that ten lamps could extinguish one lamp with their smoke. This solution does not hold water. Imagine a Hanukkah menorah on the eighth day of Hanukkah. Nine lights are burning in a small radius and yet the amount of smoke given off by the lights is insufficient to extinguish even one of them. Rabbi Obadiah from Bartenura offers a different angle. He asks rhetorically, “Where have we seen one lamp extinguish another lamp?” Nevertheless, he continues, one very bright light can conceal a dimmer light. According to the Bartenura, Joseph reassures his brothers by telling them that “If ten lamps cannot conceal one lamp, how can one lamp conceal ten lamps?” To fully understand the Bartenura, we must understand that the squabble between Joseph and his brothers was not caused by something as trivial as sibling rivalry. According to many commentators, their disagreement concerned the very future of the Jewish People. Specifically, they disagreed over the best place for the nascent Jewish nation to grow. Joseph took a cosmopolitan approach: He believed that Judaism needed to grow outside the confines of the Land of Israel, where it would have a numerically greater influence in the world. Joseph’s brothers took an isolationist approach. They believed that exporting Judaism abroad would dilute it and it would die a slow death. They believed that Joseph’s approach was an existential threat, and this was the reason they felt justified in doing away with him. When Joseph reassures his brothers, he tells them that their light – their beliefs – could not conceal his light. He had prospered in Egypt, which had become a new home to his family. His approach had been vindicated. They had no need to fear for the future of the Jewish people.
While the explanation of the Bartenura seems to tidily address all of our questions, there still remains one open issue: According to the Talmud, Joseph specifically mentions ten lamps “extinguishing (le’chabot)” another lamp. The explanation of the Bartenura hinges upon ten lamps “concealing (le’hastir)” another lamp. Let us try to massage the explanation of the Bartenura so that it fits into the wording of the Talmud. To do so, we introduce the concept of a “smoke point,” the temperature at which a heated oil stops shimmering and begins to scorch. The macromolecules in the oil begin to break down into free radicals, fatty acids and glycerides. The glycerides further break down into water and smoky acrolein, a mucous membrane irritant that can sting eyes and cause coughing. While the smoke point of an oil depends upon a host of parameters, impurities will lower the smoke point. For example, butter has a very low smoke point because it contains a high concentration of milk solids. Refining an oil raises its smoke point. Thus, it is better to sauté foods in clarified butter or ghee than in regular butter. Now let us revisit Joseph’s reassurance. Ten lamps can extinguish another lamp by heating the oil of the other lamp so that it reaches its smoke point, particularly if its fuel contains impurities. Joseph reassures his brothers by telling them that his approach had been vindicated only because he had retained his purity, his conviction, and his integrity. He can say this only after Jacob dies, after he has spent nearly four decades in Egypt. As the Mishnah in Tractate Avot [2:4] states, “Do not believe in yourself until the day you die.” Their lamps could not extinguish his lamp. How could his lamp extinguish theirs? As long as the Jewish People retain our integrity, we will thrive. There can be no greater reassurance.
Ari Sacher, Moreshet, 5784
Please daven for a Refu’a Shelema for Sheindel Devorah bat Rina, Rina bat Hassida, and Esther Sharon bat Chana Raizel.
 Rabbi Shlomo Yitzchaki, known by his acronym “Rashi,” was the most eminent of the medieval commentators. He lived in northern France in the eleventh century.
 Rabbi Yitzchak ben Asher HaLevi, known by his acronym “Riva,” was one of Rashi’s students.
 All lamps use a kind of hydrocarbon as fuel for this reason. Squalene is the main hydrocarbon in olive oil.
 Rabbi Obadiah, also known as “The Bartenura,” lived in Italy and in Israel in the fifteenth century.
 See https://www.theyeshiva.net/jewish/2621/judaism-inward-or-outward-the-great-debate-1
 Joseph lived in Egypt for 22 years before Jacob arrived and Jacob lived in Egypt for 17 years.