The extraordinarily long lives of the ante-diluvian patriarchs have always elicited debate among scholars of Sacred Scripture, especially that of Methuselah, who was just shy of a millennium when he died. We read in the fifth chapter of Genesis of Methuselah, the oldest human being who ever lived; according to the Scriptures, he lived to be 969 years old (Gen. 5:27). Methuselah was the son of Enoch, the first human to be assumed into Paradise, and was also the grandfather of Noah.
Aside from the question of whether these long lifespans are literal or not (and I see no reason why they can't be), there is a very interesting correlation here between the life of Methuselah and the coming of the great Flood. We know that Methuselah lives to be 969 years old. We also know that the Flood comes in Noah's 600th year, according to Genesis 7:11. If we work backwards from the Flood to the birth of Noah, we have 600 years. Now, from the birth of Noah back to the birth of Noah's father Lamech, Genesis tells us was 182 years. From the birth of Lamech back to the birth of his father, Methuselah, we are told that 187 years elapsed.
So, from the birth of Methuselah to the great Flood we have three periods, 187 years, 182 years and 600 years. If we add these three periods together, we come up with 969 years, the exact same span of time that Methuselah was on the earth.
%between%%between%%between%%between%What does this mean? It indicates that the Flood happened in the same year Methuselah died, which can be interpreted in two ways: (1) God (depending on how one interprets Gen. 6:3), seems to warn that man has only one hundred and twenty years left until they are judged. Since the Flood happened in the same year Methuselah died, we could not unreasonably conjecture that God was postponing the Flood until the death of Methuselah, not wanting to destroy the righteous along with the wicked.
God was, therefore, probably waiting for Methuselah to die before He sent the Flood. This is corroborated by ancient Jewish tradition; according to the Targums, Aramaic commentaries on the Old Testament, the Flood began after the seven days of mourning for the death of Methuselah were ended (source). By the way, if you do the math, Lamech, father of Noah, predeceased Methuselah by five years.
I don't know why or if this is very important, but it is interesting to point out and reminds us that these lifespans given to the antediluvian patriarchs are not arbitrary.