Midrash sur Job 36:27

We are taught in a Baraitha: R. Eliezer said: "The entire world drinks of the water of the ocean [coming from below]; as it is said (Gen. 2, 6) But there went up a mist from the earth and watered the whole face of the ground." "How can that be?" R. Joshua said to him. "Are not the waters of the ocean salty?" Whereupon he replied: "They become sweet in the clouds." R. Joshua, however, says: "The entire world drinks of the water that comes from above, as it is said (Deut. 11, 11) From the rain of heaven doth it drink water. But how is the passage: T' at there went up a mist from the earth, to be taken? It means that clouds rise towards heaven, where they open their mouths like bags and drink in the water; as it is said (Job 36, 27) For he taketh away drops of water, which are purified into rain in the mist; and the mist is porous like a sieve, through which the rain descends to the earth; as it is said (II Sam. 22, 12) Heavy masses of water, thick clouds of the skies, and the space from one drop to another is only the width of a hair. From this it may be inferred that the day of rain is as great as was the day of creation of heaven and earth; as it is said (Job 9, 10) Who doth great things which are quite unsearchable; and it is also written (Ib. 5, 10) Who giveth rain upon the surface of the earth; and it is also written (Is. 40, 28) Dost thou not know? Hast thou not heard? The God of everlasting is the Lord, etc., unsearchable is his understanding; and again it is written (Ps. 65, 7) Who setteth firmly the mountains, etc.

The firmament is similar to a lake and above the lake is a covering. From the from the lake heat condensation flows from the covering, and the condensation [as rain] descends to the midst of the salt waters [of the sea] and the rain does not mix itself [with the salt water]. Rabbi Jonah said "do not be amazed, as it is the case that the Jordan River passes through the Sea of Tiberias (the Sea of Galilee) and it does not mix itself with it; this is a miraculous thing to say! A man sifting wheat or chaff in a sieve, the grains have not descended two or three finger-breadths and they have mixed together, but these [raindrops] have traveled and traveled year after year and have not mixed themselves [with salt water]." Rabbi Yudan, son of Rabbi Shimon says "it is because he sends them down by a measured deduction, as it is said "for He draws away (yegara') the drops of water (Job 36:27)". But see how it says "and an abatement shall be made (venigra') from your assessment (Leviticus 27:18)" [showing that the financial use of this root gr' proves that God sends them down in a measured deduction]. The thickness of the earth is equal to the thickness of the firmament, as it is said "He sits above the circle (chug) of the earth (Isaiah 40:22)" [and] "He walked about the circle (chug) of the heavens (Job 22:14)". Since "circle" (chug) occurs in both verses, they are a gezeira shavah [proving the earth and firmament have the same thickness]. Rabbi Acha said in the name of Rabbi Chanina: "This is like a metal plate". Rabbi Joshua, the son of Rabbi Nehemiah, said: "They are about two or three finger-breadths". Rabbi Shimon the son of Pazzi said: "The upper waters are greater than the lower waters by about thirty xestes (pints). "Between the waters above the waters (la-mayim)" [the lamed's gematria is] thirty [thus proving his point that the waters above have thirty extra pints]. The rabbis said "they are half and half".

“All the rivers go to the sea, yet the sea is not full; to the place that the rivers go, they go there again” (Ecclesiastes 1:7).
“All the rivers go to the sea,” and from where does the earth drink?³²Which waters are provided to the earth in the form of rain? Rabbi Eliezer and Rabbi Yehoshua, Rabbi Eliezer says: It drinks from the water of the ocean, as it is stated: “A mist went up from the earth [and watered the entire face of the ground]” (Genesis 2:6).³³Thus, it is water from the earth that turns to vapor and then falls as rain. Rabbi Yehoshua said to him: ‘Isn’t the water of the ocean salty?’ He said to him: ‘They are sweetened in the clouds, as it is written: “Which the skies pour down” (Job 36:28). Where do they become what pours down? It is in the skies.’ Rabbi Yehoshua says: [The earth] drinks from the upper waters, as it is stated: “From the rain of the heavens you drink water” (Deuteronomy 11:11). The clouds ascend from the earth to the heavens and receive [the water] as though from the mouth of a bottle, as it is written: “Which distill rain to His mist” (Job 36:27). They separate them like a sieve and one drop does not touch another, as it is written: “The amassing of water, thick clouds of the skies’ (II Samuel 22:12). Why does it call them skies [sheḥakim]? It is because they crush [shoḥekin] the water.³⁴Separating the water into separate drops. Rabbi Abba bar Kahana said: Like an omasum.³⁵The third stomach in the animal that grinds the food. Rabbi Shmuel bar Naḥman said: Like the intestines of an animal.³⁶That crush the food. It is as Rabbi Yehoshua said: A day of rainfall is great, as it is equivalent to the entire act of Creation.³⁷Rabbi Yehoshua’s opinion that rainwater is from the upper waters in the heavens, which comes to earth, is consistent with his statement that this process is an act equivalent to Creation itself (Midrash HaMevoar). What is the reason? “Who performs great things beyond scrutiny and wonders beyond number” (Job 9:10); with what? “Who gives water on the face of the earth…” (Job 5:10).

... from the upper ones, as it is said, ‘from the rain of the heavens she (the land) will drink water’ [Dt 11:11]