Берешит 2:10 Каббала: Zohar, Sha'arei Orah, Pardes Rimmonim & Reshit Chokhmah

R. Eleazar said: ‘The term “These are”, as we have learnt, always implies that something spoken of before in the text is now of no account. Now it is written above in the account of the Creation¹Where also we find the expression ‘these are the generations, (Gen. 2, 4). that “A river went out from Eden to water the garden and from thence it was parted, etc.” (Gen. 2, 10). That stream which flows perennially entered the Garden to water it from the supernal waters, and brought gladness to it, making it produce fruit and seed for the universal content; and so the stream gladdened the Garden, as it is written, “And he rested on the seventh day” (Ibid. 3).

Consider this. From the day that the world was created, Noah was the first man fitted to be joined in union with the ark and to enter it, and until they were joined the world had not yet reached a stable condition. But once this had happened we read “From these all the earth was overspread” (Gen. 10, 32). These words are analogous to the expression “And from thence the river parted” (Ibid. 2, 10), of the Garden of Eden, which indicate that from this point there was a parting and diffusion of progeny into all quarters of the world.

“the seas” refer to the seven pillars which are the foundation of the earth, and over which rules the Sea of Kinnereth (R. Judah, however, maintained that the latter is filled by the others); “the rivers” are connected with the “river which went out of Eden to water the garden” (Gen. 2, 10).