It is very difficult, if not impossible, to reduce a work as complex and multifaceted as the Zohar to a few basic teachings. In a general sense, however, it is possible to gain some insight into the Zohar's world-view by focusing on a few of its central recurring themes. Let us look at one.
G-d, Torah and the Jewish People
There are three levels bound together -- the Holy One, blessed be He, the Torah and [the people of] Israel. Each of them [comprises] level upon level, hidden and revealed. The Holy One, blessed be He, level upon level, is hidden and revealed. The Torah, too, is hidden and revealed. And so too Israel is level upon level, as it is written, "He tells His words [of Torah] to Jacob, His statutes and ordinances to Israel". (Psalms 147:19) There are two levels [of the Jewish people mentioned in the verse]: Jacob and Israel. One [Jacob] is revealed and the other [Israel] is hidden" (Zohar vol. III, 73a).
The Holy One, blessed be He, level upon level, is concealed and revealed
The explanation of this statement is that all three components of the intimate bond between Israel, the Torah and G-d are locked together like the links of a chain. The Jewish people are bound to the Torah; and the Torah, being bound to G-d, draws down G-dliness into the soul. On the other hand, the soul is bound (independently of the Torah) to G-d, and via the soul, the Torah is imbued with additional illumination.
Each of the three interlinked components has a revealed and a hidden aspect. The revealed aspect of Israel comprises, in general, the life force of the soul clothed within the physical body, and its faculties -- the intellect and natural emotional characteristics with which the Jewish people are endowed. The hidden aspect of Israel is the soul as it cleaves to G-d above, and its faculties -- the hidden essential intellect possessed by the hidden recesses of the soul, and the pure, refined faith in One Creator, residing in the innermost dimensionless point of the heart.
The revealed aspect of Torah is the rational intellectual aspect of every subject in Torah, encompassing not only the life of a person from his conception to his burial, but also all matters pertaining to the entire creation. The hidden aspect of Torah lies in its divine intellect, which differs essentially from human intellect, and therefore cannot be fathomed.
The revealed aspect of the Holy One, blessed be He, is expressed in His creating worlds and all created beings and giving them life, bringing them into being at every moment, as in the saying, "In His goodness He constantly renews the work of Creation" (from the Liturgy, morning prayers). The intention is that everything in the created worlds is renewed ex nihilo as if it had just been created for the first time by "He who spoke and the world came into being."
The worlds are structured according to a specific divine paradigm.
Technically, the worlds are structured according to a specific divine paradigm -- the recurring pattern of sefirot (divine emanations) that serves as the blueprint of creation of all the worlds. The Zohar focuses on this paradigm, explaining its structure and the interactions that take place between the sefirot individually, and as partzufim (sing. partzuf -- visage). It examines the various planes of reality, called worlds, and defines their qualities and characteristics.
G-d gave us the wisdom, understanding and knowledge to discern Him from nature, its beauty and wondrous processes, by deeply contemplating His creations as in the verses, "How great are your works," (Psalms 92:6) "How manifold are your works" (Psalms 104:24). This is the secret of prayer -- an outpouring of the soul and cleaving to the Master of the Worlds. In addition, there are also certain kabbalistic meditations (kavanot) and methods (using divine names and permutations, for example) available to the initiate for ascending through the various stages of prayer and expanding one's G-d-consciousness.
The hidden aspect of the Holy One, blessed be He, is His Essence, transcending the life force with which He imbues the worlds. He is to be found within the Torah, and by its constant study, a person cleaves to G-d above and illuminates his soul below.
This bond exists in each Jew, without distinction between man and woman; old and young; learned...or ignorant.
Israel, Torah and G-d are bound together in a complete unity, as the Zohar states elsewhere, "the Holy One, blessed be He are, the Torah and Israel are all one," and their unification is by way of the revealed and hidden aspects of each of them. This is an innate relationship, not one forged by any particular activity or event. In other words, this innate relationship exists, irrespective of whether it is revealed or not. Accordingly, the bond exists in each and every Jew, without distinction between man and woman; old and young; learned, of average knowledge or ignorant. Thus we find in the Zohar that several very esoteric teachings are revealed by a child (in the section called Yenuka), or by an ostensibly simple donkey-driver.
Nevertheless, circumstances can affect the degree of awareness of this bond between Israel, the Torah and G-d. Indulgence in the hubbub of worldly matters tends to desensitize a person to intellectual and emotional appreciation of G-dly matters and their innate bond to the Creator. By contrast, a focused concentration on Torah study, and particularly the inner dimension of Torah as found in the Zohar and other kabbalistic works, brings this innate bond with the Creator into the forefront of a person's consciousness, giving them a constant awareness of G-d.
Indeed, the purpose of the soul's descent to earth is to reveal the harmony that is inherent in creation, beginning with the person himself, as the microcosm of the creation. The harmony is achieved by establishing the proper balance between the soul and the body. Inner personal peace and harmony can be attained only through ensuring the supremacy of the soul over the body, since the body can be persuaded to submit to the soul (in the case of the true mystic -- even eagerly) but not vice versa. Nevertheless, Jewish mysticism does not generally advocate asceticism and other-worldliness -- "the world was created to be a settled place," and "G-d desires a dwelling place in the lower worlds" explicitly.
Jewish mysticism, in general, and the Zohar, in particular, helps to realize this purpose of the soul by teaching us how to recognize the spirituality of matter. Kabbala explains that in every physical thing, even the inanimate, there is a "soul," which is the creative force that has brought it into being ex nihilo, and which constantly keeps it from reverting back to its former state of non-existence. It is this spark of G-dliness that is the true essence and reality of all things. And when physical matter is used for a sublime purpose or deed in accordance with the Will of the Creator, this spark is revealed. In fact, kabbalists are renowned for their strict adherence to the minutiae of the law, often going far beyond the basic requirement of the law in their fulfillment. A basic tenet of Kabbala, and of the Zohar, in particular, therefore, is that G-d can be grasped better through deed (the fulfillment of mitzvot) than through meditation.
[Translation and commentary by Moshe Miller.]