Kabbalah zu Bereschit 2:2

Rabbi Elazar said that we have learned that whenever the term "These (Heb. אֵלֶּה)" appears, it always annuls something previously mentioned. Now, it is written in the portion of Beresheet, "And a river went out of Eden to water the garden; and from thence it was parted" (Gen. 2:10). This river (corresponding to Yesod) is drawn and comes out of Eden, (which is Chochmah), and enters the garden, (Malchut), to water it from the supernal waters and bring it pleasure, making it produce fruit and seed. This gives satisfaction to everyone. The garden is pleased which brings pleasure to the river. As it is written: "Because in it He rested" (Ibid. 3). And it is also written: "And He rested on the seventh day" (Ibid. 2) (He rested in the Garden that is Malchut). This is the secret of the matter, for it produces offspring, and no other Sefirah can produce any fruit.

So all the actions, whether it be those of the first [three] days, [which are of Fire, Water, and Air] or the last [three] days, [which involved Netzach, Hod, and Chesed] were dependent on the day of the Shabbat, [which is Malkuth]. Therefore, it is written, "And on the seventh day Elohim completed His work which He had done" (Gen 2:2). This refers to the Shabbat and the fourth leg of the throne.