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:
Diez generaciones desde Adán hasta Noaj. Para informarnos cuán sufrido es. Por todas estas generaciones siguieron enojándolo—hasta que trajo sobre ellos las aguas del diluvio. [Usted tampoco se sorprende de que haya sufrido mucho con los idólatras durante todos estos años, de que hayan estado sometiendo a Sus hijos, porque lo fue aún más con los idólatras de las (diez) generaciones desde Adán hasta Noaj—hasta que fueron destruidos en el diluvio.] Diez generaciones desde Noaj hasta Abraham. Para informarnos cuán sufrido es. Por todas estas generaciones siguieron enojándolo—hasta que Abraham vino y tomó sobre sí la recompensa de todos. [Hizo buenas acciones correspondientes a lo que todos deberían haber hecho—por lo que todos fueron rescatados por su mérito. Y así como tomó sobre sí el yugo de mitzvoth en este mundo sobre y contra todos ellos, también recibió para que el mundo viniera recompensa sobre y contra todos ellos. Por cada hombre tiene dos acciones, una en Gan Eden; el otro, en Gehinnom. Si es meritorio, toma su parte y la de su vecino (el malhechor) en Gan Eden. Si es culpable, toma su parte y la de su vecino (el tzadik) en 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.”