Both the health of the body and the health of the soul, are closely linked together

Freely translated from a letter of the Rebbe addressed to "all campers in summer camps, everywhere," written three months before the Yom Kippur War.

Tammuz 5733

I hope and pray that you are making the fullest use of the present summer days to gain new strength and strengthen your health - both the health of the body and the health of the soul, which are closely linked together. And since the health of the soul is bound up with the Torah, which is "our very life and the length of our days," and with its mitzvot, "by which the Jew lives," you are surely doing your utmost in regard to Torah study and the observance of the mitzvot; in which case you may be certain for the fulfillment of the promise - "Try hard, and you will succeed."
I wish to emphasize one point in particular, in connection with the forthcoming "Three Weeks." You are, no doubt, familiar with the events and significance of these days. The point is this:
I want you to consider carefully the special merit which Jewish children have, a privilege which affects our entire Jewish people, to which King David refers in the following words: "Out of the mouths of babes and infants You have ordained strength - oz...to still the enemy and avenger" - including also the enemy that has caused the "Three Weeks" and still seeks vengeance to this day. In other words, the way to vanquish and silence the enemy is through the study of the Torah, called "strength" (oz), by the mouths of young children. Indeed, so great is their power, that our Sages of blessed memory declare: "The whole world exists only by virtue of the breath of little Jewish children, whose breath is pure and free of sin," referring to children who have not yet reached the age of responsibility for wrongdoing, that is, boys and girls of pre-Bar/Bat Mitzva age.
In this connection it is necessary to bear in mind the words of our Prophet Isaiah (in the first chapter): "Zion will be redeemed through justice (mishpat) and her returnees through righteousness (tzedaka)." "Mishpat," here, means that through the study of the Torah and the observance of its mitzvot, especially the mitzva of tzedaka, the Redemption is brought closer. And tzedaka - in the light of what has been said in the beginning of this letter - includes both tzedaka for the body and tzedaka for the soul. Tzedaka for the body is, simply, giving tzedaka to a poor man, or putting money in a tzedaka box. Tzedaka for the soul is done by helping one's classmates and friends spiritually - that is, to encourage them in matters of Torah and mitzvot, through showing them a living example of how Jewish boys and girls should conduct themselves, and also by talking to them about these things.
Since it is my strong wish, and also great pleasure, to be your partner in this tzedaka activity, I have sent out instructions to give each and every one of you a token amount of money in the currency of your country, which is to be my participation in the said tzedaka campaign.
May G-d bless each and every one of you and grant you success in all the above, especially in your Torah learning and practice of tzedaka, in a steadily growing measure, so that even when you return home from camp and throughout the next school-year (may it be a good one for all of us) you will - with renewed vigor and in good health, in body as well as in soul - go from strength to strength in your study of Torah with diligence and devotion, and that your studies be translated into deeds - in the practice of mitzvot with beauty; and all this should be carried out with joy and gladness of heart.
And may we all very soon, together with all our Jewish brethren, merit the fulfillment of the prophecy that these days of the Three Weeks be transformed from sadness into gladness and joy.
With the true and complete Redemption through our righteous Moshiach, "who will reign from sea to sea, and from the river to the ends of the earth...and all the earth will be filled with G-d's Glory."