The following section of the Zohar expounds on the secret of the "Merkava" - literally "chariot". The Chariot described in Ezekiel's prophetic vision (Ezekiel chapter 1) is the vehicle for divine revelation in the world of Yetzira, the next spiritual world beyond the spiritual dimension of our physical world, the world of Asiya.

Joseph harnessed his chariot in order to ascend to a higher level of divine revelation….

Meditation on various aspects of the Merkava was the focus of an important stream of Jewish mysticism. Here the Zohar explains that Joseph harnessed his Merkava - his chariot - in order to ascend to a higher level of divine revelation. The explanation revolves around the understanding of the word "Chaya" (literally "wild animal" - plural "Chayot") which means "animating force" in the Zohar.

"Joseph harnessed his chariot and went up to meet his father Israel in Goshen." (Gen. 46:29)

Rabbi Yitzchak began his discourse, citing the verse "There was a likeness of an expanse above the heads of the Chaya, like the color of the awesome ice, spread out above their heads from above" (Ezekiel 1:22).

This verse has already been expounded [as referring to the animating forces - Chayot - in the world of Yetzira]. But come and see [the how the term "Chaya" is used in different contexts in this and preceding verses, so that] there is Chaya above Chaya [- a hierarchy of levels].

[The highest level] is "Holy Chaya" - above the heads of the Chayot. And there a higher form of "Chaya" [i.e. higher than the Chayot, but lower than Holy Chaya] which stands above every other Chaya, and controls all of them, so that when this Chaya gives illumination to all of them, then they travel [upwards] on their journeys, and one transmits [life-force] to the other and controls the other.

When the various levels of a person's soul…have been rectified and harnessed in the proper way, then a person is able to ascend….

Accordingly, there are three levels of Chaya: "Holy Chaya", which is chochma; "Chaya" (bina) which is above Chayot and controls the Chayot, and "Chayot",the life-forces that animate Zeir Anpin and interact with one another. (Mikdash Melech)

Now when all of these aspects of the Merkava are set in their proper place, what does the verse declare? "Above the expanse that was over their heads was the appearance of sapphire stone in the likeness of a throne, and upon the likeness of the throne there was a likeness like the appearance of a man upon it, from above" (Ezekiel 1:26).

Elsewhere, the Zohar explains that the throne is the world of Beriya. (Pardes, Archai)

We have established that the throne of precious stone stands upon four legs.1 And upon that throne is the likeness of a man2 And upon with whom to unite in communion, and be blessed, as is proper.

When [all these levels] are rectified within the person himself, so that all the levels are a Merkava [i.e. a vehicle] for G‑dliness, then it is written, "Joseph harnessed his chariot and went up to meet his father Israel in Goshen."

In other words, when the various levels of a person's soul - Nefesh (corresponding to the word of Asiya), Ruach (corresponding to Yetzira), Neshama (corresponding to Beriya) - have been rectified and harnessed in the proper way, then a person is able to ascend to the level of Chaya (Atzilut) and commune with the Divine Presence as revealed in Zeir Anpin of Atzilut, referred to in the verse as "his father, Israel", and in the vision of the Merkava as "the likeness of a man".

This is what Joseph achieved when "he harnessed his chariot".

[Zohar I, p. 210b; translation and commentary by Moshe Miller
First published by Fiftieth Gate Publications and Seminars.]