Zohar, Bereshit 38

1AND GOD SAID, LET THERE BE A FIRMAMENT IN THE MIDST OF THE WATERS, AND LET IT DIVIDE WATERS FROM WATERS. R. Judah said: ‘There are seven firmaments above, all in the realm of supernal holiness, and the Holy Name is completed through them. The firmament mentioned here is in the midst of the waters;

2it rests upon other Hayyoth, separating the upper from the lower waters. The lower waters call to the upper and drink them in through the medium of this firmament, because all the upper waters are collected in it, and it then transmits them to these Hayyoth, and so they draw from there.

3It is written: “A garden shut up is my sister, my bride, a spring shut up, a fountain sealed” (S. S. 4, 12). This firmament is called a “garden shut up”, because the whole is enclosed and embraced in it. It is called a “spring shut up”, because the supernal stream as it courses enters it but cannot issue, the waters being congealed. For the north wind blows on them, and so they become congealed and cannot issue, being made into ice; nor would they ever issue were it not for a wind from the South which breaks up the ice.

4The appearance of this highest firmament is like that of the ice which collects all the waters. Similarly it collects waters and separates the upper from the lower waters. When we said above that it was in the middle, this refers to that firmament which was produced from this one, but this one is above and rests on the heads of the Hayyoth.’

5Said R. Isaac: ‘There is a membrane in the inside of the human body which separates the upper from the lower part of the trunk, and which imbibes from the upper part and distributes to the lower part; so is this firmament between the waters….’