What does Genesis 5:30 mean?

As with most of the other men listed in this chapter, verses 30 and 31 describe Lamech as having additional children, and then passing away. According to the numbers given in this passage, Lamech lived 595 more years after Noah was born. Since we're told in Genesis 7:6 that Noah was 600 years old when the floodwaters came on the earth, this means Lamech died just 5 years before the flood.

As with Methuselah, there is a sad aspect to reading about Lamech's many children. One way or another, only Noah, his wife, and their family would be rescued from the flood. The rest of Lamech's offspring will not survive. One also has to wonder how Lamech felt about the state of mankind. According to Genesis 6:5, the human race was rapidly decaying into horrific evil. And yet, men like Lamech had lived on earth at the same time as men like Adam and Seth. The contrast between these eras would have been especially clear to someone like him.