Комментарий к Берешит 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 שבעה, G’d commanded both Noach and the animals to enter the ark already seven days prior to the onset of the deluge in order to assign to them their various accommodations and in order to get them used to their change in diet, especially the flesh eating beasts which had to adjust to a vegetarian diet. According to the Midrash (Sanhedrin 108) Metushelach had died during these days and G’d suspended the decree until after the days of mourning for him had expired. He had been a righteous man and it was no more than appropriate that his passing should be noted with appropriate eulogies and mourning rites. We know that these eulogies were spread over a period of seven days from Genesis 50,10 where, even though Yaakov had already been mourned for 70 days in Egypt prior to the transfer of his remains to the cave of Machpelah in the land of Canaan, he was eulogized again. We had already demonstrated that according to the data provided by the Torah Metushelach must have died at the time the deluge commenced.