'Lifetime' in the Bible

"Hear this, you elders! Listen, all of you residents of the land! Has there ever been anything like this during your lifetime, or even when your ancestors were alive?

A day of doom and gloom, a day of clouds and shadows like the dawn spreads out to cover the mountains a people strong and robust. Never has there been anything like it, neither will anything follow to compare with it, even through the lifetime of generation upon generation."