עֲשָׂרָה דוֹרוֹת מֵאָדָם וְעַד נֹחַ, לְהוֹדִיעַ כַּמָּה אֶרֶךְ אַפַּיִם לְפָנָיו, שֶׁכָּל הַדּוֹרוֹת הָיוּ מַכְעִיסִין וּבָאִין עַד שֶׁהֵבִיא עֲלֵיהֶם אֶת מֵי הַמַּבּוּל. עֲשָׂרָה דוֹרוֹת מִנֹּחַ וְעַד אַבְרָהָם, לְהוֹדִיעַ כַּמָּה אֶרֶךְ אַפַּיִם לְפָנָיו, שֶׁכָּל הַדּוֹרוֹת הָיוּ מַכְעִיסִין וּבָאִין, עַד שֶׁבָּא אַבְרָהָם וְקִבֵּל עָלָיו שְׂכַר כֻּלָּם:
Dieci generazioni da Adamo fino a Noach. Per informarci di quanto sia longanime. Per tutte queste generazioni hanno continuato a farlo arrabbiare—fino a quando non ha portato su di loro le acque del diluvio. [Anche tu non ti meraviglia che abbia sofferto a lungo negli idolatri in tutti questi anni di aver soggiogato i suoi figli, poiché lo era ancora di più per gli idolatri delle (dieci) generazioni da Adamo a Noach—fino a quando non furono distrutti dall'alluvione.] Dieci generazioni da Noach fino ad Abramo. Per informarci di quanto sia longanime. Per tutte queste generazioni hanno continuato a farlo arrabbiare—fino a quando Abramo venne e prese su di sé la ricompensa di tutti. [Ha fatto buone azioni corrispondenti a ciò che avrebbero dovuto fare tutti—pertanto furono tutti salvati nel suo merito. E proprio mentre prendeva su di sé il giogo di mitzvoth in questo mondo sopra e contro tutti loro, così ricevette che il mondo venisse ricompensato sopra e contro tutti loro. Perché ogni uomo ha due azioni, una in Gan Eden; l'altro, a Gehinnom. Se è meritorio, prende la sua parte e quella del suo vicino (il malfattore) in Gan Eden. Se è colpevole, prende la sua parte e quella del suo vicino (il tzaddik) in Gehinnom.]
Avot DeRabbi Natan
And why was it necessary to bring all those people into the world? This teaches you that even as all those generations continued to anger the Holy Blessed One, He did not bring the flood upon them because of the righteous and saintly among them. And some say that as long as Methuselah was alive, the flood did not come upon the world; and even when Methuselah died, it was still held off for another seven days, as it says (Genesis 7:10), “And it was seven days, [and the waters of the flood were on the earth].” What was happening during those seven days? These were the [seven] days of mourning for that righteous man, who had prevented the punishment. That is why it says, “And it was seven days.”
Another interpretation of, “And it was seven days”: This teaches that the Holy Blessed One fixed a specific time, after 120 years, hoping that they might repent. But they did not, and so it says, “And it was seven days” [i.e., the final seven days of the countdown].
Another interpretation of, “And it was seven days”: This teaches that the Holy Blessed One changed the order of the world [which was created in seven days] for them, and had the sun rise from the west and set in the east, hoping that maybe they would understand and become afraid and repent. But they did not, and so it says, “And it was seven days.”
Another interpretation: This teaches that the Holy Blessed One set a table for them, and gave them a taste of the World to Come, so that they would gather together and say to one another, “Oy, for we have lost all this goodness, and we have caused the destruction of our descendants (from the earth), as it says (Genesis 6:12), “And God saw the earth, and it had been destroyed.”