Mesora: A human body surely benefits from physical rest, if he is tired. However, rest per se is not always a 'good'. Exercise is also a must for one's health. So we see King Solomon's words are again substantiated (See Ecclesiastes, Chapter 3) i.e., there is a time for everything, but not everything is good - all the time.
However, we cannot stop there. "Sabbatical rest" cannot be defined as a good, if we measure it in simple, physical terms. All of man's actions truly miss their mark and purpose, if the entire scope of reality and man's ultimate purpose is ignored. When asking what is the "good" for man, (rest, happiness, eating, etc.) while excluding man's ultimate goal (loving G-d), you cannot answer the question within the framework of "true reality". The answer must, by definition, be wrong. If you wish to know what is good for man, we must take into account man's true purpose and all that is true and real.
So what is man's true purpose? How can we identify it? We must study reality, and arrive at what is absolute truth. Reality is founded on G-d's existence, and His goal for man. Sinai is eternal proof of G-d's existence, and His desire that man follow the Torah. The Torah is man's one goal, and purpose. If man denies G-d's existence, man's existence is of no value. All his rest, exercise, reading, kindness, and all activities including Torah observance, fail to be realized as a service in gaining knowledge of G-d, and adhering to His laws. Once G-d is removed from the equation, man is not living with any value. For example, it may seem that one cares for another person with his "kindness", but if he cares merely to make people happy or healthy, but not for the sake of a happy/healthy life...."to follow Torah", then the happiness and healthiness is limited only to the sphere of man's Earthly stay. Man, in such a case, has missed his only opportunity to arrive at knowledge of G-d, by using intelligence, which was given for this primary objective. Man has completely failed to operate in reality, and his life is a waste.
When asking if rest is a good, we must ask, "rest for what goal?" One may reply, "to be strong to work and raise his family." Sounds admirable. We then ask, "why is it good to do these?" If we do not eventuate in the primary goal of approaching G-d through our intellect, then all actions in man's life are bereft of the absolute "good", i.e., loving G-d. In such a case, rest, kindness, Torah observance, etc., are not a "good", in G-d's terms. They are the "means", with no "ends", as defined by G-d,...as defined by ultimate reality.
Any Torah law or tenet, performed or accepted, without conviction of G-d's existence, forfeits its purpose. And if a man lived his entire life with such a philosophy, he forfeits his life. Even more, Rashi in Deuteronomy says, if one does not understand the idea of a mitzvah, he obtains no benefit through that mitzvah. He must still keep that command, but the entire goal is not achieved. Every command and principle contained in Torah aims at man's appreciation of the Source of the Torah - G-d. If one's studies and actions do not culminate in a realization and appreciation for G-d, then he misses the entire purpose of those ideas and commands.
Reader: So, what would you say about a person of no awareness of G-d, finding a copy of Torah on a park bench which it turns out has been edited to delete references to G-d as the Source of Torah and the Authority behind Torah? The person reads through the Torah and decides to try to live by the precepts it contains, following to the letter all of the mitzvahs, etc... 1)Would that person, in your opinion, derive any benefit from being a Torah Person? (Do we need to know who invented aspirin or what aspirin contains for aspirin to cure a headache?)
Mesora: As I said, without conviction in G-d's existence, and that Torah was created and given by G-d, the observer lacks any appreciation for the Creator, therefore, such actions fail in their primary goal. Man's life was a waste.