10. The days of our years in them are seventy years. He who thinks this is short and complains about this brevity of a very short life, does he ask a letter of God and not rather another life, which is eternal? For, in fact, since by these things he wanted to show that the wrath of God is this brevity of life for all, and should therefore be shunned and another sought, namely, in Christ, for that reason he says, Is not this your wrath? Have we not fainted away? Is this not a calamity? Have not all our days passed away, so that 70 years is their entire length? Why, then, do we act and look for only those things which are so unstable and so few and so short? Whom would these three not move? For instability, even if the days were many and long, is still one condition that is calamitous enough. But now the days are also few and short. And that toward which we are moving is eternal. Quite properly, then, there follows below We are soon gone, and we fly away. For if they were stable, one would be enough. But if they were many and endless, they would again be enough, even if they were short and unstable. But he says, “in them,” that is, in their very nature. For in relation to eternity a thousand years are as yesterday that is past.
Luther’s works, vol. 11: First Lectures 2