The healthier the soul is, the greater is its control of the body and the ability to correct the body's failings.

The Rebbe, Mind Over Matter, p.311.

There's an interesting expression that Jews use to congratulate one another when they do good for others, and that expression is "Yasher Koach." It's an unusual phrase because on top of being a misspelling and a mispronunciation, it's also idiomatic and enigmatic to boot.

But if it's so untranslatable, why analyze it at all? Why not just let it remain an inscrutable epithet for "Thanks, you're amazing," and let it go at that?

It's an unusual phrase because on top of being a misspelling and a mispronunciation, it's also idiomatic and enigmatic to bootThere are at least three good reasons to take a closer look: (1) Everything in Judaism is meaningful - whether it's Torah, its interpretation or customs based on it. (2) This particular phrase is especially rich, as it reflects all of these - a verse of Torah, its deeper meaning, and a long-standing custom, and (3) New research relating good and evil to physical power gives us a completely fresh perspective on what "Yasher Koach" is all about.

With proper diction, the expression is really supposed to be "Yishar kochacha" which literally means "May your strength be enriched" or "May your strength be straight." These days, the closest idiom would be "More power to you."

Its origin is the Talmud where it comments on G‑d's endorsement of Moses breaking the Tablets in response to the Israelites worshipping the Golden Calf.

And how do we know that the Holy One, blessed be He, gave His approval? Because it is said, "Which you have broken" (asher shibarta). Resh Lakish said, (Yishar kochecha sheshibarta) "All strength to you [i.e., congratulations] for breaking them."1

But isn't it strange? Why would a man, Moses, whose whole life embodied Torah trash the very stones in which it was engraved? And engraved by the Hand of G‑d, no less. The basic answer is that Moses' life mission was to serve and protect the Jewish nation, so he tore up the contract, so to speak, by destroying the only written record of the Torah they had transgressed. Only by putting loyalty before law was Moses able to break the tablets.

The details are instructive too. The Sages relate2 that as Moses approached the scene, the letters flew off, his hands became weak, and the Tablets broke. This was no Charlton Hestonesque temper tantrum throw-the-plate-against-the-wall outburst. Moses, despite his absolute commitment to G‑d and His Torah, knowingly sacrificed Torah truth for Jewish continuity. In response, G‑d Himself cooperated and literally removed the message from the medium. The tzaddik decreed and the One Above fulfilled.3

How did Moses manage to carry it before the sin?At the end, what was left? A lump of stone. As the beloved Torah Tablets, Moses could carry them; as mere rock, it was too much to bear. Our Sages say4, each tablet was a block of sapphire 6x6x3 handbreadths in size. Following R' Chaim Na'eh that a handbreadth is 8 cm, and knowing sapphire to be four times as dense as water, and water to be one gram per cubic centimeter, the total weight of the two Tablets was about 440 kg or nearly 1000 pounds!

No wonder he found it heavy. But how did he manage to carry it before the sin? Was it a miracle or was he really that strong? Of course Moses was a G‑dly person, so normal rules need not apply. Nonetheless, there must be a lesson here for us.

To understand this, let's consider the case of Bruce Anderson of Anchorage, Alaska.5 One spring afternoon, he was repairing his 1985 Volkswagen station wagon when it slipped off the jacks and pinned him to the ground. Trapped beneath the car, Bruce's cries for help summoned his 17-year-old son, Riley. Realizing that his father was in trouble and that help was far away, Riley did the amazing: he took hold of the bumper and lifted the 2500 lb. vehicle off of his dad.

For the love of his dad, 2500 pounds was not too heavy for Bruce to lift. For the love of G‑d, 1000 pounds was not too heavy for Moses. Yet Moses chose to carry something much heavier - the burden of leading the entire Jewish people.

Where does strength come from? Diet and exercise are only part of the picture. According to fascinating experiments in social psychology recently completed by Kurt Gray and his colleagues and Harvard University, good (as well as evil) deeds and thoughts are potent triggers of physical power.6

Volunteers were given a dollar and told to keep it or donate it to charity. The decision made, they were asked to hold a weight for as long as they could. Surprisingly, those who had done a good deed were able to bear the load for almost ten seconds longer than the others. In a follow-up experiment even thinking about doing good increased their physical stamina after the fact.

Moral fortitude unlocks a wellspring of strength that even permeates our physical musclesScientists have discovered that doing and even thinking good for others gives "more power to you." Moral fortitude unlocks a wellspring of strength that even permeates our physical muscles. Moses had that dual strength and Jews have been blessing each other with it for thousands of years since then. It's nice to know that the scientists are finally catching on to the causal connection between goodness and strength as well.

In our time, no one exemplifies these qualities better than the Lubavitcher Rebbe. Sleeping only two or three hours a night, eating very little, standing all day greeting and blessing thousands of visitors one by one, handing to each of them dollars for charity or other items. Where does all this strength come from? From his goodness, no doubt.

Among the qualities a person must have in order to become a bona fide prophet, Maimonides lists self-discipline, Torah expertise, scrupulous mitzvah observance, and physical strength. Understanding that Torah scholars and prophets don't generally "work out" so much, perhaps that strength comes from all the good that they do.

More than anything else, the times of Redemption are characterized by two things: Moral excellence and complete wellness. What science and Torah both seem to be telling us is that pursuing the former will get us the latter. Do another mitzvah and get another "Yasher Koach" to bring Moshiach now!