"The shattering of the vessels" (in Hebrew, "Shevirat haKeilim") of the world of Tohu is the key concept in explaining the basic problem of diverseness and multiplicity in Creation as well as the origin of evil and is a central component in the Arizal's system of Kabbala, where it receives a full exposition
The concept of Shevirat haKeilim is linked together with the mystical account of the eight kings who "reigned in the land of Edom before any king ruled over the Israelites" (Gen. 36:31) and the Midrashic account of the building and destruction of the primordial worlds (Bereishit Rabba 3:7, 9:1), as will be explained below. Although the idea of Shevirat haKeilim is also found in several sections of Zohar (in Sifra d'Tzni'uta, Idra Rabba and Idra Zuta), the concept and its ramifications are very difficult to understand there without the elucidation of the entire subject in the writings of Rabbi Yitzchak Luria. (For this reason, even here, many readers will find the roll-over glossary feature essential for comprehending this important piece.)
The Arizal explains that when it arose in the Divine Will to create the finite world, the first step was to "withdraw" or conceal the infinite Or Ein Sof in the process known as "the first constriction" or "tzimtzum harishon". The first "world" (plane of existence) that came into being after the tzimtzum is called Adam Kadmon. But even though Adam Kadmon is a post-tzimtzum world, it is still a "meta-world", so-to-speak - undefined, unified, and transcending time, comprising a single transcendent primordial thought. Light emitted from the eyes of Adam Kadmon … signifies a descent from an internal, essential level to an external 'sensory' level…
The existence of the finite world as we know it, and as G‑d intended it, is still not possible in Adam Kadmon due to its extremely lofty state. In order for a finite world to exist, the light in Adam Kadmon had to go through several more stages of quantitative contraction and descent. In one of these stages of descent, one of the several types of light emitted from Adam Kadmon is manifested as ten individual qualities or attributes that act as separate, independent points of light, or quanta of energy. Technically, this is called "light emitted from the eyes" of Adam Kadmon or "or ha-einayim". This metaphorical term signifies a descent from an internal, essential level to an external "sensory" level where the beam of light is refracted into discrete quanta. Each of these points is an extremely powerful concentration of light (the level of keter of each of the ensuing sefirot) as it descends from Adam Kadmon. These sefirot compose the world of Tohu (chaos or disorder).
The first "world" outside of Adam Kadmon is called Akudim. In it is the first development of a vessel, such that ten degrees of light are bound together (in Hebrew, "akudim") in a single vessel (Writings of the Ari, Shaar HaHakdamot, Derush 1 b'Olam HaNikudim).
The existence of vessels [for the lights that issued forth from Adam Kadmon] begins only in the world of Akudim - in which there is but one general vessel for all the ten lights - and below. Subsequently, the world of Nikudim [another name for Tohu] was emanated, in which ten vessels were formed for the ten lights. All of them were the aspect of keter of the ten sefirot, so that there were ten lights of keter of the ten sefirot. Each of these ten keter-lights had an individual vessel. The remaining nine parts of the lights [i.e., chochma, bina, chesed, etc.] in each of the sefirot were incorporated within the keter-light of each of the sefirot. For this reason they are referred to as ten "nekudot", meaning individual "points" of light, rather than as ten complete sefirot… Now these ten sefirot were emanated in such a way that they were situated one above the other. (Ibid., Shaar HaHakdamot, Derush 1 b'Olam HaNikudim) The sefirot of Tohu were situated one above the other in a single line … unlike the array of the sefirot in the world of Tikun, in which the sefirot are arranged in harmonious triads…
The fact that the sefirot of Tohu were situated one above the other in a single line indicates that they act as independent entities, unlike the array of the sefirot in the world of Tikun, in which the sefirot are arranged in harmonious triads. Thus each sefira of Tohu existed as an autonomous fiefdom, so to speak, independent of, and even in opposition to, the others. Moreover, each sefira in Tohu is the manifestation of an absolute and quintessential aspect of the light of Adam Kadmon (the level of keter of each type of light, as explained above).
Furthermore, the vessels themselves were in a state of immaturity and were therefore unable to contain the intense light flooding them.
"…Only the malchut aspect of the seven sefirot was emanated… and therefore they were called nekudot, for nekuda and malchut are synonymous. . In addition, not only were they [in a state of immaturity], even in this state they were not clothed one within the other, nor were they bound together as a unit. Nor were they divided into arrays, [namely,] of kindness in the right array, severity in the left array and the mitigation between them in the middle array [as in Tikun]." (Etz Chaim, shaar 9, ch. 8)
Due to the intensity and exclusivity of the lights and the inability of their vessels to contain them, the vessels of the lower sefirot of Tohu shattered and the lights they contained remained above. The fragments of these vessels then fell to lower levels, becoming absorbed into the various worlds below the world of Tohu. The three uppermost vessels had the ability to contain the lights designated for them and did not die…
"Since the lights of these ten nekudot were so intense and powerful… the [vessels] did not have the power to contain them and the vessels "died", meaning to say, they descended below to the level that is now called [the world of] Beriya. This descent was their demise. But this was only as regards the seven lower nekudot, whereas the three uppermost vessels had the ability to contain the lights designated for them and did not die… The vessels of the seven lower [nekudot] descended to the world of Beriya… but their lights remained above, exposed, without vessels." (Ibid.)
Scripture hints at this process in describing the succeeding kings of Edom: "These are the kings who ruled in the land of Edom before any king ruled over the Israelites. Bela son of Be'or became king… He died and was succeeded as king by Yoav… Yoav died, and he was succeeded as king by Chusham… Chusham died, and was succeeded by… etc." (Gen. 36:31-39). The Arizal explained that this refers to the sefirot of Tohu, each of which rules exclusively, and then shatters and "dies."
Thus Tohu was a primordial form of existence that "was created in order to be destroyed, and destroyed in order to be rebuilt" in a superior form (see Mevo L'Chachmat HaKabbala part 2, shaar 6, ch. 7). The order of creation that followed the disintegration of the world of Tohu is called the world of Tikun (literally translated as "rectification" or "restoration"). Regarding Tikun, the Torah states, "And G‑d looked over everything that He had made, and indeed it was very good" (Gen. 1:31). In the words of the Midrash (Bereishit Rabba 3:7; 9:2), as explained by the Arizal, "these please Me" refers to the sefirot of Tikun, whereas the sefirot of Tohu "do not please Me".
The sefirot of Tikun were emanated in such a way that they work together interdependently and harmoniously, as partzufim (literally, "visages" - sing. "partzuf") - compound structures of the sefirot. A partzuf is a metaphorical figure of human likeness, used to represent the expansion of an individual sefira (or group of sefirot) into a configuration with ten sefirot of its own. Partzufim include Atik Yomin, Arich Anpin, Abba, Imma, Zeir Anpin (ben), Nukva (bat)]. As mentioned, the partzufim work as symbiotic harmonious systems instead of the discrete, independent, overpowering nekudot of Tohu. What could not be elevated into Atzilut remained in Beriya…
Although the sefirot of Tohu shattered and "died," nevertheless, a residue of the lights that were contained in the vessels remained clinging to the fragments of the vessels. These are referred to by the Arizal as the 288 nitzotzin (literally "sparks") - the initial number of fragments from the vessels that broke. The entire process is alluded to in Scripture in the first couple verses of Genesis: "In the beginning of G‑d's creating the heavens and the earth, when the earth was tohu and void, and darkness was on the surface of the depths, and the sovereignty of G‑d hovered (in Hebrew "merachefet") above the surface of the waters…." The Arizal explains that the word "merachefet" is actually a compound of two words: "met" and "rapach" - signifying that 288 (the numerical value of rapach) fragments had died (in Hebrew, "met") - an allusion to the shattering of the vessels of Tohu into 288 initial sparks. (Mevo She'arim, shaar 2, ch. 8)
Although the fragments of the vessels initially fell into the world of Beriya, when their rectification (tikun) began, the most refined aspects of the vessels were able to ascend and became absorbed in the world of Atzilut. What could not be elevated into Atzilut remained in Beriya and became an integral part of it. What could not be absorbed into Beriya then descended into Yetzira and Asiya. The aspects of the vessels that could not be absorbed in even the lowest realm of holiness became the vitality of the realms of impurity, known as the kelipot. (Ibid.)
The shattering of the sefirot of Tohu is not a coincidence, nor does it signify a flaw in the creative process. On the contrary, it serves a very specific and important purpose, which is to bring about a state of separation or partition of the light into distinct qualities and attributes, and thereby introduce diversity and multiplicity into creation, as explained above. In addition, the shattering of the vessels of Tohu allows for the possibility of evil, and gives man the opportunity to choose between good (for which he gains reward) and evil (for which he is punished). Thus G‑d's attributes of chesed and gevura - the attributes from which reward and punishment derive - are revealed in the world , which is one of the primary purposes of creation. (See beginning of Otzrot Chaim)