Genesis 8:2

Gen 8:2 The fountains also of the deep and the windows of heaven were stopped, and the rain from heaven was restrained;

Ver. 2. And the rain from heaven was restrained.] These four keys, say the Rabbis, God keeps under his own belt: 1. Of the womb; 2. Of the grave; 3. Of the rain; 4. Of the heart. "He openeth, and no man shutteth; he shutteth and no man openeth". {Rev 3:7}

John Trapp, A Commentary or Exposition upon All the Books of the Old and New Testament (1647–1656) — public domain. Text from a community e-Sword module.

8:2 underground waters . . . torrential rains: See study note on 7:11-12.

Tyndale Open Study Notes — © Tyndale Open Resources, licensed CC BY-SA 4.0. Text via the HelloAO Bible API.

The fountains also of the deep, and the windows of heaven, were stopped,.... The passages which let out the subterraneous waters in great quantity upon the earth, and the clouds of heaven, which poured down water upon it like spouts, were stopped from sending forth any more, as they had from the first of the flood unto one hundred and fifty days from thence: Jarchi observes, that it is not said that "all" the fountains of the deep, as when they were broken up, Gen 7:11 because some of them were left open for the use and benefit of the world; besides, some must be left for the return of the waters:

and the rain from heaven was restrained: which seems to confirm what has been before observed, that after the rain of forty days and nights it ceased not to rain, more or less, though not so vehemently, until the end of an hundred and fifty days, and then it entirely ceased.

John Gill's Exposition of the Whole Bible (1746–1763) — public domain (CC PDM 1.0). Text via the HelloAO Bible API.

The fountains also of the deep, and the windows of heaven were stopped. WrkSYiw, from rksrgs; to surround, to enclose; literally, were shut up; ejpekalufqhsan (LXX.). Their opening was described in Gen_7:11. And the rain from heaven was restrained. aleKYiw, literally, was shut up, from alK to close. Cf. kleiw, kwluw, kolouw, celo, occulo (Gesenius, Furst), sunesceqh (LXX). At the end of the forty; (Gen_7:12; Augustine, Willet) at the end of the 150 days (Aben Ezra, Murphy).

The Pulpit Commentary (1880–1919), ed. H.D.M. Spence-Jones & Joseph S. Exell — public domain. Text from a community e-Sword module.

ויסכרו מעינות AND THE FOUNTAINS … WERE STOPPED –– When they were opened, it was stated that all fountains were opened (7:11), whilst here the word all is omitted: the reason is that such of them as were essential to the world were left unstopped, such as the hot springs of Tiberias and their like (Sanhedrin 108a).

ויכלא means was restrained. withheld, as (Psalms 40:12) “Thou wilt not withhold (תכלא) thy mercies” and (Genesis 23:6) “None of us will withhold (יכלה) from thee.’’

Rashi on the Tanakh — English translations: “The Judaica Press complete Tanach with Rashi, translated by A. J. Rosenberg” (CC BY 4.0); “Pentateuch with Rashi's commentary by M. Rosenbaum and A.M. Silbermann, 1929-1934” (public domain); “The Metsudah Tanach series, Lakewood, N.J” (CC BY 4.0); and “The Book of Joshua, Metsudah Publications, 1997” (CC BY 4.0). Text via Sefaria.

ויסכרו, they were shut, i.e. prevented from adding further turbulence on the surface of the waters which had flooded the globe. As a result of the wind blowing, the earth gradually began to dry out, the moisture being blown away, gradually. However, these subterranean wells were not all of them shut off. This enabled some of the waters on the surface of the globe to flow back gradually into the bowels of the earth from which they had come forth. While it is true that at the time these waters had risen to the surface they had found many more apertures through which to rise, and their appearance on the surface had been rapid, now it seeped back at a much slower pace.

וארבות השמים, those “windows” of the heavens had already closed after the forty days of rainfall. Now no more water inundated the earth either from above or from below.

ויכלא הגשם, the Torah mentions this to tell us that not even normal rainfall still occurred during this period when the earth returned to normal.

ויסכרו, the word is spelled with the letter כ,.which in this instance is used instead of the customary letter ג, in the root סגר. The construction is not unique, as we also find it in Psalms 63,12 כי יסכר פי דובר שקר, “when the mouth of liars is stopped.”

Radak on the Tanakh — English translations: “Sefaria Community Translation” (CC0 1.0 (public-domain dedication)); “Eliyahu Munk, HaChut Hameshulash” (CC BY 4.0); “Rabbi Mike Feuer, Jerusalem Anthology” (CC BY 4.0); and “R. David Kimhi on the first book of Psalms, Translated by R.G. Finch, London, 1919” (public domain). Text via Sefaria.