The meaning of this is, in fact, that form and similitude extend only from the fourth level, which is Malkhut. The vessels are drawn from it, in the place of the recipients, but not at all from the first nine sefirot, which are Keter, Ḥokhma, Bina, and Tiferet.48As explained in the Petiḥa LeḤokhmat HaKabbala, section 58. Recall that since Tiferet includes the other six lower sefirot, the four sefirot mentioned here actually represent all nine remaining sefirot.
However, in the world of Tikkun (rectification), there is a combination of the attribute of judgment with the attribute of mercy. This means that [God] raised the sefira of Malkhut, which is considered the attribute of judgment, and brought it into the sefira of Bina, which is considered the attribute of mercy.49As stated in the Petiḥa LeḤokhmat HaKabbala, section 58; see there. The process of the ascent of Malkhut to the place of Bina is called the second constriction.
This process ultimately allows the vessel of Malkhut to become rectified (the process of rectification referenced here) and able to receive the supernal light. Therefore, from that point onward, the vessels of Malkhut become rooted in the sefira of Bina, as stated here. This is why when the Zohar begins to speak about the actual root of the images, which are the vessels, it states that they are in Malkhut, and then afterward it states that they are in Beria.
This is because of the force of the combination that was performed for the sake of the rectification of the world. The Sages likewise stated:50Bereshit Rabba 12:15. “The Holy One, blessed be He, initially created the world with the attribute of judgment; [when] He saw that the world could not exist, He combined with it the attribute of mercy.”