Yetzirah means formation, shaping. Cordovero connects the word to the verse in Genesis: "the L-rd G-d formed man, dust of the ground." The Torah uses this verb for dust, he says, because it designates a reality thicker and more revealed than Beriah. He also quotes Isaiah: "this people I formed for Myself."
It is the world of the angels. Massekhet Atzilut describes it this way: "I formed him, this is the world of Yetzirah; there are the holy chayot that Ezekiel son of Buzi the priest saw, there are His servants who do His will." It lists ten classes of angels, seraphim, ofanim, keruvim and the others, each with its appointed officer, and above them Metatron. Cordovero says the same: after the Throne, G-d formed ten classes of angels, all attached to Metatron, the prince of the Face, who is for them "like the heart in the body, the dwelling of life, from which all the limbs draw their life."
The Tikkunei Zohar draw a lesson from this about prophecy. If you ask what Ezekiel saw, says the text, he saw only "the likeness" of the chayot, not the chayot themselves. It is like a king who sends a document marked with his seal: in the Sefirot of Atzilut is the very image of the King; in those of Beriah, the King's seal; in those of Yetzirah and among the angels, the imprint of the seal in wax. That is why the prophet writes: "a likeness, as the appearance of a man." Cordovero concludes that Ezekiel's visions are located in Yetzirah, neither in Beriah nor in Atzilut.
For Cordovero, Yetzirah also governs ordinary time: on weekdays and in exile, the light reaches us through it, and this is what the Zohar calls the King's weekday garments. The Ari, in Etz Chaim, links this world to the vav of the Name, to Zeir Anpin and to ruach, the spirit; he quotes the formula: "six Sefirot nest in Yetzirah."
Keep the image of the seal. The lower one goes, the more distant the imprint, and what one sees is only a likeness; but it is always the same King who is marked in the wax. Even the prophet does not see beyond the imprint, and that is already a great deal.
