The Sabbath: A Cornerstone of Judaism
The Ten Commandments, revealed to the Jewish people on Mount Sinai, contain the fundamental principles of religious belief, morality, and ethics by which every devout individual guides his life. The commandments to believe in God and honor one's parents, along with the injunctions against murder, stealing and adultery are all included in the famous and time honored code. Beliefs and practices such as these are clearly essential components of the lifestyle and philosophy of any religious person.
When examining some of the Ten Commandments, however, it is much more difficult to perceive their profound significance. Belief in God and abstention from unethical and immoral activity are certainly cornerstones of any religion; however, they were not the only commandments etched into the stone tablets.
The fourth commandment, that of observance of the Sabbath, is clearly neither a fundamental belief nor a rule of ethical or moral conduct. The Sabbath is a ritualistic institution, a commemoration of God's creation of the Universe. As the Torah explicitly states, "For in six days God made the heavens and the earth, the seas and all that is in them and He rested on the seventh day; therefore, God blessed the seventh day and sanctified it."
The question arises quite powerfully - why has a relatively insignificant rite of commemoration been placed among the ranks of "thou shalt not kill" and "thou shalt not steal" - laws of the utmost importance, foundations upon which all of civilized society rests? The question of the apparent overemphasis of the Sabbath's importance does not stop here. In Exodus 35:2 the Torah prescribes the most severe death penalty, that of stoning, for the Sabbath violator. The Talmud states emphatically and unequivocally that "anyone who willfully violates the Sabbath is considered to have worshipped idolatry." These statements clearly contradict the commonly held opinion that the Sabbath is a relatively unimportant ritual, a mere celebration of the birthday of the Universe.
In order to resolve these difficulties, one's idea of the nature of the Sabbath must be clarified considerably. On the Sabbath, it is true, we commemorate God's creation of the Universe by refraining from all creative activity (melakha). In reality, however, the significance of the Sabbath extends much further than a mere "commemoration."
On the Sabbath, we are given an opportunity to approach the Universe in an entirely different manner than we are accustomed to during the week. Sunday through Friday, we manipulate God's creation in accordance with our wishes - changing things to better suit our desires, improving things to better satisfy our needs, and creating things to help us accomplish our tasks more efficiently. On the seventh day, we step back from any creative involvement in the Universe and attempt to appreciate it objectively - not as a tool for accomplishing our needs and desires, but as an awesome manifestation of the infinite wisdom of the Creator. We contemplate the perfection and grandeur of the Universe, and we are compelled to realize what an insignificant component of it we truly are.
Indeed, despite all of our thoughtfulness and creativity we remain helplessly subject to the unchanging laws of the magnificent Universe of which we are but a small part. Jewish law demands that we partake of three meals during the Sabbath so that we are physically satisfied and emotionally prepared to enter the world of abstract thought. The practices of lighting candles, bathing, and donning fine clothing prior to the Sabbath all serve to emphasize the honorable nature of the day's pursuits, and to create an atmosphere ideal for and conducive to intellectual activity. In fact, according to the strict legislation of Jewish law, one is required to refrain from any discussion that does not pertain to the acquisition of knowledge or that may distract one from involvement in its apprehension.
On the Sabbath, we approach the Universe with our minds rather than our hands, and we relax, free of the troubles of everyday life, to enjoy the most delightful beauty we are capable of perceiving - the profound wisdom manifest in Nature. As the Psalmist states, "The heavens declare the glory of God, and the firmament displays His handiwork." Our Sages teach us that human perfection and true happiness can be achieved only through the acquisition of knowledge. In the words of Maimonides, "when a person ponders His great and wondrous works and creations and recognizes thereby His wisdom that is immeasurable and infinite he immediately loves, praises, and extols and is filled with a great desire to know the Supreme Being...And when he contemplates these things he is immediately drawn back with great reverence, realizing that he is a tiny, insignificant, unenlightened creature standing with his frail intellect before He Who is perfect in knowledge." 
Similarly, he writes: "the commandment to love God requires that we analyze and gain an understanding of His commandments, statements and actions until we acquire true knowledge of Him and experience by way of this knowledge the ultimate enjoyment...Thus I have explained that through contemplation you will arrive at true knowledge and experience the aforementioned enjoyment, and the love will of necessity follow."
This concept is constantly reiterated throughout Scripture,  the Talmud and the writings of later sages. In the Ethics of the Fathers we are taught that "an ignorant person cannot be righteous." Our Sages believed wholeheartedly that the laws of the Torah were fashioned purely for the purpose of guiding all of us toward true wisdom and understanding. The Torah itself expresses this in Deuteronomy, "For this is your wisdom and your understanding in the eyes of the people, who will hear all these statutes and say, surely this great people is a wise and understanding nation." The Sabbath, a day set aside for thought, contemplation, and honest appreciation of the wisdom inherent in the Universe, is the clearest expression of our unique philosophic system in which the acquisition of knowledge is viewed as the ultimate goal for mankind.
Idolatry, however, stands in absolute contradiction to this approach to the Universe. Faced with the daunting grandeur of God's creation, the idolater is gripped with an overpowering sense of helplessness and despair. As a child, he had been sheltered and provided for by his parents. Even during the most difficult times, he had been able to find comfort in the knowledge that his parents would always be there for him - to feed him, clothe him, and protect him from all harm. Now that he has attained maturity, the feeling of security which had sustained him since childhood has been torn from him mercilessly. Peering out at the vast Universe, he witnesses the wonders and the horrors of Nature: life-giving rainfalls and destructive floods, plentiful harvests and widespread famines, the miracle of birth and the mystery of death. The anxiety and feeling of utter defenselessness before Mother Nature is too much for the primitive individual to handle.
Thus, the idolater "creates", by way of his imagination, myriads of forces, spirits, and deities whom he can manipulate to fulfill his desires. Once again he is safe, shielded from harm by "gods" who are greater than he and who regulate and direct the laws of nature. Dominated by his physical needs and desires, he is compelled to deny the absolute and unchanging system of the laws of Nature anytime that it conflicts with his wishes. Imprisoned in shackles of self-centered emotion, he is unable to perceive knowledge and to enjoy its beauty and profundity. Whenever the idolater meets with difficulty in the satisfaction of his instincts he appeals to his gods through prayer or sacrifice, begging them to assist him by causing the Universe to operate in accordance with his will. With a little imagination the idolater has restored the peaceful situation of his childhood.
Einstein, in observation of this phenomenon, wrote "Now what are the feelings and needs that have led men to religious thought and belief in the widest sense of the word?....With primitive man it is above all fear that evokes religious notions - fear of hunger, wild beasts, sickness, death. Since at this stage understanding of causal connections is usually poorly developed, the human mind creates illusory beings more or less analogous to itself on whose wills and actions these fearful happenings depend. Thus one tries to secure the favor of these beings by carrying out actions and offering sacrifices, which, according to the tradition handed down from generation to generation...makes them well disposed toward a mortal." Sigmund Freud wrote along similar lines, "It can clearly be seen that possession of these (religious) ideas protects him (the idolater) in two directions -against the dangers of nature and Fate, and against the injuries that threaten him from human society itself."
The idolatrous personality cannot conceive of the Universe outside of the framework of his own needs and desires. In his philosophy, the Universe's very existence is only valuable in so far as it provides him with the tools to pursue and satisfy his instincts. Thus, the concept of a Sabbath is utterly alien to the primitive individual. In his mind, an attempt to relate to the Universe with anything other than one's animalistic drives would be unheard of, even objectionable. The base, sense-perception oriented philosophy of idolatry is diametrically opposed to any system of thought which would produce a Sabbath. A day for contemplation of abstract beauty and objective appreciation of the Universe has no place in the lifestyle of the individual steeped in idol worship.
It now becomes clear why the Sabbath is so essential to Judaism, as well as why desecration of the Sabbath is considered by our Sages to be tantamount to idol worship. Violation of the sanctity of the Sabbath is equivalent to a rejection of the philosophic principles upon which it is founded; and it is the rejection of these principles, as our Sages rightly observed, that constitutes the very essence of idolatry.
Observance of the Sabbath clearly distinguishes Judaism, a religion based on knowledge and created to facilitate intellectual perfection, from the pagan religions, all of which were formed in attempts to provide false security to primitive mankind. Belief in idolatrous religious principles is truly destructive to human beings, causing them to deny reality, convincing them to shun wisdom, breeding ignorance and demanding blind faith. For all intents and purposes, the idolater conducts his life like an animal, obeying his instincts and retarding his intellectual growth.
The Sabbath, on the other hand, brings one who observes it properly the truest form of human happiness, that which results from the acquisition of knowledge and understanding.  It expresses quite clearly the unique philosophy and value system of Judaism. In the poetic words of the Sabbath prayer service, "those who observe the Sabbath with joy will forever possess glory...those who love its ideas have chosen true greatness."
Tractate Chullin 5a, as well as Maimonides' Laws of the Sabbath 30:15, and numerous other places in the Talmud.
The Prophetic books abound with praise of the greatness and importance of the Sabbath. For example, in Isaiah 58:13-14, we read "If you restrain your foot because of the Sabbath, from pursuing your business on My holy day; if you refer to the Sabbath as 'a delight', to the holy day of the Lord as 'honorable'; and you honor it, by not pursuing your business or speaking of worthless matters, then you shall delight yourself in knowledge of the Lord; and I will cause you to ride upon the high places of the earth..." Statements like these are made quite frequently in the book of Isaiah as well as in other books of the prophets.
In the words of King David (Psalms 8:4-5), "When I consider Your heavens, the work of Your fingers, the moon and stars that You have established - what is man that You should take notice of him?"
This is not meant to imply that Judaism rejects the concept of Divine Providence. On the contrary,it is a fundamental tenet of Jewish philosophy that God extends a measure of His Providence to individual human beings which is in proportion to the degree of perfection which they have attained. As Psalms asserts (91:14), "For he has yearned for Me and I will deliver him, I will elevate him because he knows My name." Our Sages teach us that God's "name" refers to His wisdom as it is expressed in His actions, i.e., the laws of nature. (See Maimonides' Guide for the Perplexed, Book One, Chapters 61-64, where this topic is dealt with in its entirety, as well as the commentaries of Rabbi Obadya Sforno and Ibn Ezra on Exodus 3:14-15 and 6:2-3 and the commentaries of Ibn Ezra and Radak on Zechariah 14:9.)
Tractate Shabbat 113a as well as Maimonides' Laws of the Sabbath 24:4-5 and Shulchan Aruch, Mishnah Berurah and Tur Shulchan Aruch Section 307.
Maimonides, Laws of the Fundamentals of the Torah, Chapter II, Law II.
Compare Albert Einstein, "Everyone who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the Universe, a spirit vastly superior to man and one in the face of which we with our modest powers must feel humble."(Albert Einstein, The Human Side, Helen Dukas and Banesh Hoffman, p.33)
Maimonides, Book of The Commandments, Positive Commandment III.
In fact, two books of the Bible, Proverbs and Ecclesiastes, are devoted exclusively to praise of the life guided by wisdom.
Note the statement of King Solomon (Proverbs 3:13-18), "Happy is the man who finds wisdom, and the man who acquires understanding. For the value of it is greater than the value of silver, and its gain than that of fine gold. She is more precious than rubies, and all things you may desire are not to be compared to her...Her ways are ways of pleasantness, and all her paths are peace. She is a tree of life to those who hold fast to her; happy are those who rely upon her."
Ethics of the Fathers, 2:5
Maimonides discusses this point at length in his Guide for The Perplexed, as do Gersonides (see, for example, his introduction to his commentary on the Bible and his comments on Genesis chapters 1-3), Rabbi Obadya Sforno (see, for example, his introduction to his commentary on the Bible and his comments on Genesis chapters 1-3, as well as his introduction to his commentary on the Book of Ecclesiastes), Rabbi Abraham Ibn Ezra, the Chinuch (see, for example, his explanation of the philosophic basis for the commandment to fast on the Day of Atonement), the Meiri (see, for example, his introduction to his commentary on the Talmud), Rabbi David Kimchi (also known as the Radak; see, for example, his introduction to his commentary on the Bible as well as his introduction to the Book of Joshua), Rav Saadiah Gaon, Rabbi Bachya ibn Pekuda, Rabbi Joseph Albo, Rabbi Moshe Chaim Luzzato (refer, for example, to his work entitled The Way of Wisdom), and many later authorities.
Similarly, the Psalmist declares (Psalms 19:8), "The ordinances of the Lord are trustworthy, making the simple one wise."
Compare the words of King David (Psalms 92:1, 2 and 5-6), "A psalm, a song for the Sabbath day. It is good to give thanks to the Lord, and to sing praise to Your name, O Exalted One....For You have gladdened me through Your deeds, when I perceive the works of Your hands I sing glad song. How great are Your deeds, O Lord; exceedingly profound are Your thoughts."
For an explanation of the concepts of prayer and sacrifice in the highly sophisticated and rational framework of Judaism, see "The Role of the Sacrificial Service in Judaism" by this author.
Albert Einstein, Religion and Science, 1930. Found in Ideas and Opinions.
Sigmund Freud, The Future of an Illusion, 1927.
The stark contrast between the world view of the idolater and that of the Jew is the basis of the Talmudic adage (Tractate Kiddushin 40a), "Anyone who accepts idolatry is considered to have rejected the entire Torah, and anyone who rejects idolatry is considered to have accepted the entire Torah." Along similar lines, Maimonides stated in his Guide that "the principle objective of the Torah is the extirpation of idolatry."
Einstein expressed his unconventionally religious love for and devotion to knowledge in the following manner: "To know that what is impenetrable for us truly exists and manifests itself as the highest wisdom and the most radiant beauty whose gross forms alone are intelligible to our poor faculties , this knowledge, this feeling...that is the core of the true religious sentiment. In this sense....I rank myself among profoundly religious men."(Albert Einstein, The Man and his Theories, Hilary Cuny, P.149)
Maimonides writes (Laws of the Sabbath, 30:10), "...This was the custom of the pious men of old on the Sabbath day: they would pray the morning and additional service in the Synagogue, then return to their houses to eat the afternoon meal; after this they would go to the House of Study..until the afternoon service.." Similarly, the Jerusalem Talmud states, "The Sabbath was given to the Jewish people only to provide them with free time to engage in Torah study." See also the Meiri's introduction to his commentary on the Talmud, the Sefer HaChinuch Mitzvah 31 and 32, Maimonides in his final letter to his son, the introduction of Abraham son of Maimonides to his work The Guide for Worshipers of God, the commentaries of Rabbi Abraham ibn Ezra, Rabbi Obadya Sforno, Rabbi David Kimchi and Gersonides on Genesis 2:3 and Exodus 20:8-11, the Shulchan Aruch, Mishna Berurah and Tur Shulchan Aruch 290:2, and Midrash Tanchuma Vayakhel.
Siddur, Additional Prayer for the Sabbath (Mussaf)