I've heard that Methuselah's name was given to him by Enoch in response to a prophecy concerning the flood. Since he seems to have died in the year of the flood (according to the Masoretic and Samaritan texts), it's not surprising that interpreters would search for evidence for a deeper meaning to his (record-breaking) life. But there's very little to go on other than the meaning of his name. Here is the sum of the biblical account of his life:
When Enoch had lived 65 years, he begot Methuselah. After the birth of Methuselah, Enoch walked with God 300 years; and he begot sons and daughters. All the days of Enoch came to 365 years. Enoch walked with God; then he was no more, for God took him.
When Methuselah had lived 187 years, he begot Lamech. After the birth of Lamech, Methuselah lived 782 years and begot sons and daughters. All the days of Methuselah came to 969 years; then he died.—Genesis 5:21-27 (NJPS)
The two interpretations I've seen are:
- "man of the dart" (or possibly "spear")
- "he shall send his death" or more provocatively "when he is dead it shall be sent"
See, for instance this answer, which references Gleanings from Genesis and this article, which also references Dictionary of Old Testament Proper Names.
Do these definitions of the name "Methuselah" stand up and, if so, what is the significance to our interpretation of Genesis 5?