Genesis 7:4

כי לימים עוד שבעה FOR YET SEVEN DAYS — These are the seven days of mourning for the righteous man Methuselah for whose honour the Holy One, blessed be He, had regard, and therefore postponed punishment. Go and calculate the years of Methuselah and you will find that they came to an end (i. e. he died) in the six hundredth year of Noah’s life (which coincided with the date of the Flood) (Sanhedrin 108b). כי לימים עוד FOR YET [SEVEN] DAYS — What is meant by עוד "yet", "more"? A further period of time: this period (seven days) additional to the 120 years of respite that was promised (Sanhedrin 108b). ארבעים יום FORTY DAYS — corresponding to the period of a child’s formation, for by their sinning they had troubled their Creator to form embryos of illegitimate children (Genesis Rabbah 32:5).

כִּי֩ לְיָמִ֨ים ע֜וֹד שִׁבְעָ֗ה אָֽנֹכִי֙ מַמְטִ֣יר עַל־הָאָ֔רֶץ אַרְבָּעִ֣ים י֔וֹם וְאַרְבָּעִ֖ים לָ֑יְלָה וּמָחִ֗יתִי אֶֽת־כׇּל־הַיְקוּם֙ אֲשֶׁ֣ר עָשִׂ֔יתִי מֵעַ֖ל פְּנֵ֥י הָֽאֲדָמָֽה׃

For in another seven days, I will cause it to rain upon the earth forty days and forty nights; and every living substance that I have made will I destroy from off the face of the earth.