(א) וַֽיְהִי֙ כִּֽי־הֵחֵ֣ל הָֽאָדָ֔ם לָרֹ֖ב עַל־פְּנֵ֣י הָֽאֲדָמָ֑ה וּבָנ֖וֹת יֻלְּד֥וּ לָהֶֽם׃
(ב) וַיִּרְא֤וּ בְנֵי־הָֽאֱלֹהִים֙ אֶת־בְּנ֣וֹת הָֽאָדָ֔ם כִּ֥י טֹבֹ֖ת הֵ֑נָּה וַיִּקְח֤וּ לָהֶם֙ נָשִׁ֔ים מִכֹּ֖ל אֲשֶׁ֥ר בָּחָֽרוּ׃
(ג) וַיֹּ֣אמֶר יְהֹוָ֗ה לֹֽא־יָד֨וֹן רוּחִ֤י בָֽאָדָם֙ לְעֹלָ֔ם בְּשַׁגַּ֖ם ה֣וּא בָשָׂ֑ר וְהָי֣וּ יָמָ֔יו מֵאָ֥ה וְעֶשְׂרִ֖ים שָׁנָֽה׃
(ד) הַנְּפִלִ֞ים הָי֣וּ בָאָ֘רֶץ֮ בַּיָּמִ֣ים הָהֵם֒ וְגַ֣ם אַֽחֲרֵי־כֵ֗ן אֲשֶׁ֨ר יָבֹ֜אוּ בְּנֵ֤י הָֽאֱלֹהִים֙ אֶל־בְּנ֣וֹת הָֽאָדָ֔ם וְיָלְד֖וּ לָהֶ֑ם הֵ֧מָּה הַגִּבֹּרִ֛ים אֲשֶׁ֥ר מֵעוֹלָ֖ם אַנְשֵׁ֥י הַשֵּֽׁם׃ {פ}
(ה) וַיַּ֣רְא יְהֹוָ֔ה כִּ֥י רַבָּ֛ה רָעַ֥ת הָאָדָ֖ם בָּאָ֑רֶץ וְכׇל־יֵ֙צֶר֙ מַחְשְׁבֹ֣ת לִבּ֔וֹ רַ֥ק רַ֖ע כׇּל־הַיּֽוֹם׃
(ו) וַיִּנָּ֣חֶם יְהֹוָ֔ה כִּֽי־עָשָׂ֥ה אֶת־הָֽאָדָ֖ם בָּאָ֑רֶץ וַיִּתְעַצֵּ֖ב אֶל־לִבּֽוֹ׃
(ז) וַיֹּ֣אמֶר יְהֹוָ֗ה אֶמְחֶ֨ה אֶת־הָאָדָ֤ם אֲשֶׁר־בָּרָ֙אתִי֙ מֵעַל֙ פְּנֵ֣י הָֽאֲדָמָ֔ה מֵֽאָדָם֙ עַד־בְּהֵמָ֔ה עַד־רֶ֖מֶשׂ וְעַד־ע֣וֹף הַשָּׁמָ֑יִם כִּ֥י נִחַ֖מְתִּי כִּ֥י עֲשִׂיתִֽם׃
When humankind began to increase on earth and daughters were born to them, the [males among the] divine beings saw how pleasing the human women were and took wives from among those who delighted them.
God said, “My breath shall not abide in/judge humankind forever, since it too is flesh; let the days allowed them be 120 years.”
The Nephilim were on the earth in those days and also later than that, when divine beings cohabited with the human women, who bore them offspring. They were the heroes of old, the men of names (or destruction).
God saw how great was human wickedness on earth; how every plan devised by the human mind was nothing but evil all the time.
And God regretted having made humankind on earth. With a sorrowful heart, God said, “I will blot out from the earth humankind whom I created–humans together with beasts, creeping things, and birds of the sky; for I regret that I made them.”
(ח) וְנֹ֕חַ מָ֥צָא חֵ֖ן בְּעֵינֵ֥י יְהֹוָֽה׃ {פ}
But Noah found favor/grace/acceptance in God's eyes.
Sforno: Chen implies groundless favor. Because Noach did not actively spread knowledge of Hashem he was not worthy that others should be saved on his account. Thus it was an act of groundless favor to him that his sons and daughters-in-law were spared.
Why might God have chosen Noach to be the one to save humanity?
Lamech named his son Noach because the word means "rest,." When Adam and Eve were expelled from Gan Eden, they were told that they would work the land with difficulty; toil and thorns. Rashi says, "For until Noah came people had no agricultural instruments and he prepared such for them."
What might Rashi's comment say about God's decision to be gracious/merciful to Noach?
וְהָי֣וּ יָמָ֔יו מֵאָ֥ה וְעֶשְׂרִ֖ים שָׁנָֽה׃
"let the days allowed [humans] be 120 years."
Why might the Creator decide to limit the lifespan of a person? This verse comes in between two verses having to do with "divine" male beings cohabiting with human women, so we might assume it's there for a reason.
The Malbim: Hashem saw that their long life spans were not to their benefit because after years of struggle the body inevitably defeated the soul, dragging it down to its own level.
Another reason 120 is mentioned:
Ibn Ezra: We see the same idea in Yet 40 days, and Nineveh shall be overthrown (Jonah 3:4). God gave them one hundred and twenty years in which to repent and save themselves, or to remain unrepentant and perish.
How can we compare and contrast the story of Noah with the story of Jonah?
(יא) וַתִּשָּׁחֵ֥ת הָאָ֖רֶץ לִפְנֵ֣י הָֽאֱלֹהִ֑ים וַתִּמָּלֵ֥א הָאָ֖רֶץ חָמָֽס׃
(יב) וַיַּ֧רְא אֱלֹהִ֛ים אֶת־הָאָ֖רֶץ וְהִנֵּ֣ה נִשְׁחָ֑תָה כִּֽי־הִשְׁחִ֧ית כׇּל־בָּשָׂ֛ר אֶת־דַּרְכּ֖וֹ עַל־הָאָֽרֶץ׃
(יג) וַיֹּ֨אמֶר אֱלֹהִ֜ים לְנֹ֗חַ קֵ֤ץ כׇּל־בָּשָׂר֙ בָּ֣א לְפָנַ֔י כִּֽי־מָלְאָ֥ה הָאָ֛רֶץ חָמָ֖ס מִפְּנֵיהֶ֑ם וְהִנְנִ֥י מַשְׁחִיתָ֖ם אֶת־הָאָֽרֶץ׃
The earth became corrupt before God; the earth was filled with lawlessness. When God saw how corrupt the earth was, for all flesh had corrupted its ways on earth, God said to Noah, “I have decided to put an end to all flesh, for the earth is filled with lawlessness because of them: I am about to destroy them with the earth.
Sforno: I will destroy the climate which could support life on earth by interfering with the sun’s orbit and rearranging it from the beginning of the deluge for the entire future. This accounts for the lifespan of man having been drastically reduced after the deluge. The climate of the earth changed, there were greater extremes of heat and cold, the produce of the earth was considerably less capable of supporting a long lifespan. As a by-product of this deterioration in the quality of the vegetable products, man was allowed to eat meat as a compensation.