On the Shortness of Life — Lucius Annaeus Seneca

It is not that we have a short time to live, but that we waste much of it. We are not poor in time; we are wasteful of it. Life is long enough, and a generous amount has been given for the greatest achievements, if the whole of it were well invested. But when it drains away in luxury and indifference, when it is devoted to no good purpose, then at last, under the compulsion of death, we realize that it has gone before we knew it was going. So it is: we are not given a short life, but we make it short. We are not ill-supplied with time, but wasteful of it. Life is long enough for the one who knows how to use it.