On the last day of his life, Moshe bids farewell to the Jewish People [Devarim 31:2]: “Today I am one hundred and twenty years old. I can no longer go or come, and G-d said to me, ‘You shall not cross this Jordan [River].’” Moshe is old. He is feeble. And because of sin he committed at Mei Meriva, he has been punished by not being permitted to cross the Jordan River into Israel. The time has come for Moshe to leave this world.
One cannot read this verse without blinking in disbelief. A frail and sickly Moshe? The Torah itself attests that when Moshe died [Devarim 34:7] “His eye had not dimmed nor had he lost his [natural] freshness”. He might have been one hundred and twenty years old but he had the strength and the vigour of a man half his age. So what was he telling the Jewish People?
Rashi, the most famous of the medieval commentators, who lived in France in the eleventh century, explains, “One might think [this means] that Moshe’s strength had ebbed [and that is why he could no longer go or come. But this cannot be so…] What then is [the meaning of] ‘I can no longer [to go or come]’? [Here it means:] ‘I am not permitted [go or come]’, because authority was taken from him and granted to Joshua.” Moshe was telling the Jewish People that he could easily have gone on for another hundred and twenty years only G-d wouldn’t allow him to do so.
The Ramban, who lived a century after Rashi in Spain and in Israel, disagrees with Rashi’s thesis, writing simply that Rashi “was wrong”. The Ramban asserts that Moshe was trying to comfort the Jewish People, who were about to lose their leader, their Rabbi, and their father figure in one fell swoop. Moshe accomplishes this by telling them that he is too old to continue and that “they have no need for [him] any longer”. He is not telling them the truth; he is telling them what they need to hear. Rabbi Ovadiah Seforno, who lived about three centuries after the Ramban, puts a finer point on the Ramban’s explanation. According to the Seforno, when Moshe mentions his age, he is telling the people “there is no reason to be sad that someone of my age has to die. According to any life expectancy and law of nature, I am no longer fit to go on living by natural means.”. When Moshe says that he can no longer come or go, he is telling them, “even if I were still able, I would not be able to function physically as a leader should, such as leading you in the conquest of the Land of Israel, as I am suffering from symptoms of old age.” And when Moshe says that G-d has forbidden him from crossing the Jordan River, he means “even if I were physically capable of leading you, the fact that G-d told me that I would not cross the Jordan would have made my leadership pointless. You are therefore better off without me so that you will be able to cross over.” Moshe gives them three good reasons to appreciate that they must move on.
Rabbi Samson Rafael Hirsch, who served as an Orthodox Rabbi in Frankfurt am Main in the nineteenth century, offers an explanation that puts an interesting spin on things. Rabbi Hirsch explains that even though according to the laws of biology, Moshe was no longer fit to go on living via “natural means”, he was still alive and kicking at the age of one hundred and twenty because G-d had kept him young via “supernatural means”. Moshe had a job to do and so G-d needed to make sure that Moshe was physically able to perform his job. Moshe’s job was to bring the Jewish People to the edge of the Jordan River, where Joshua would then take over and lead them into the Land of Israel. Now that Moshe’s job had concluded, G-d would let nature take its course and Moshe would begin to show his age. As a human being well into his second century, he would be no longer able to continue to lead his people.
This interplay between natural and supernatural is illustrated by a story in the Talmud in Tractate Ta’anit [25a]: “One Shabbat evening, Rabbi Hanina ben Dosa saw that his daughter was sad. He said to her: ‘My daughter, why are you sad?’ She said to him: ‘I confused a vessel of vinegar for a vessel of oil and I lit the Shabbat lamp with vinegar. Soon the lamp will be extinguished and we will be left in the dark’. He said to her: ‘My daughter, what are you concerned about? He Who said to the oil that it should burn can say to the vinegar that it should burn’. It was taught: That lamp burned continuously the entire day.” It is only “natural” for oil to burn because G-d wants it that way. Nature acts the way nature acts only because G-d wants it that way. If G-d wants vinegar to burn, then he can make that physical behaviour “natural” as well. The laws of physics describe G-d, they do not define or limit Him. All laws of physics are, in a way, supernatural.
Let’s try to understand the science of what is going on here. Liquids do not burn. It is the liquid vapour combined with the oxygen in the air that burns. The flammability of a liquid is categorized by its “flash point”, the minimum temperature at which sufficient vapour is given off the liquid to form an ignitable mixture with air. According to the U.S. Occupational Safety and Health Administration (OSHA), a liquid classified as “flammable” has a flash point of less than 100◦ F, or 37.8◦ C. Liquids that are not flammable must be heated in order to reach their flash point. Now here’s the thing: the flash point of glacial acetic acid, pure vinegar, is about 102.4◦ F, or 39◦ C. The temperature in Jerusalem last week was higher than that. Last Friday night, the daughter of Rabbi Hanina ben Dosa could have lit the Shabbat lamp with vinegar. The border between natural and supernatural is sometimes extremely hazy.
This can help us understand an inconsistency in the continuation of Moshe’s farewell address. After Moshe tells the Jewish People that he cannot cross over the Jordan River, he tells them [Devarim 31:3] “G-d Himself will cross over before you; and He Himself will wipe out those nations from your path and you shall dispossess them. Joshua is the one who shall cross before you, G-d has spoken.” Who will be “crossing over” before the Jewish People – will it be G-d or is it Joshua? Moshe seems to address this question two verses later [Devarim 31:5]: “Be strong and resolute, be not in fear or in dread of them; for G-d Himself marches with you: He will not fail you or forsake you.” What happened to Joshua? In order to proceed, we must differentiate between “crossing over” and “marching with”. According to Rabbi Meir Leibush ben Yechiel Michel Wisser, known as the Malbim, who lived in the Ukraine in the nineteenth century, “crossing over” means “the quick and decisive defeat of an enemy”. “Marching with”, on the other hand, is an expression of intimacy, in which two entities progress together towards the same goal. Rolling this understanding back into the scripture, Moshe is telling the Jewish People that G-d Himself will help them quickly and decisively defeat their enemies. Joshua will be the vehicle through which G-d accomplishes this. G-d will continue to rule over the laws of nature to achieve His goals and the border between the natural and the supernatural will continue to remain fuzzy. Joshua will fight with bows and with arrows, with armour and with shields. Nevertheless, the arrows will always somehow hit their targets with deadly precision and the armour will deflect even the most dangerous armour-piercing rounds. Joshua will be successful because G-d Himself marches together with the Jewish People, Hand in hand, protecting them, comforting them, and guiding them.
One day, Moshe tells his people, you will build missiles that fly far beyond the horizon through a window into a room in which Hezbollah leaders are plotting their next attack. You will build interceptors that hit rockets that are flying at more than five times the speed of sound with nearly infinite precision. G-d will be marching with you. Be not in fear or in dread. Never stop marching. He will take care of the physics.
Shabbat Shalom and stay healthy.
Ari Sacher, Moreshet, 5780
Please daven for a Refu’a Shelema for Yechiel ben Shprintza and David ben Chaya.
 Not everyone merits having the supernatural morphing into the natural. Rabbi Hanina ben Dosa was especially saintly.
 This is why it is safe to air freight missiles containing live rocket motors and warheads. They will only ignite at very high temperature and pressure and are completely safe at room temperature.
 Acetic acid is considered “combustible” as per OSHA classification. On its Material Safety Data Sheet (MSDS), acetic acid is listed as “Easily ignited by heat, spark or flames.”
 See the explanation of the Vilna Gaon on Bemidbar [22:21-22].