TT #21 · Parashas Noach · Second Aliyah · Passuk 7:10
And it came to pass after the seven days that the waters of the Flood were upon the earth.
Torah Temimah points to Sanhedrin 108b (Rav — the seven days of Methuselah’s mourning).
E-Daf image — Sanhedrin 108b (size=3)
Shas / HebrewBooks PDF of the daf
English: “And it came to pass after the seven days” — What is the nature of these seven days? Rav said: These are the days of mourning for Methuselah, to teach you that the eulogy (or mourning period) of the righteous delays the calamity from coming.
Custom (identification of the seven days with the mourning of a righteous man).
The mourning period of the righteous delays calamity; the seven days before the Flood were the days of Methuselah’s mourning.