Our life on earth is brief. This becomes obvious to anyone who thinks about it. Our time is short. So, what do we make of this fact?
It's interesting to see how people end up playing with the concept of time. For the Scientist, time becomes an idol, the false creator god. If you deny that God is involved in creation you must substitute billions and billions of years.
Medieval Rome did the same thing - but with Purgatory. So you want to have wickedness now - well, we know you can't work it off now... so we'll give you thousands, millions of years to work it off in purgatory. The mammoth nature of time once again used to replace the action of God - this time the justifying power of His Word.
There is a way in which we can think about time being brief here - considering the following from Luther: "It is certainly true that every Christian who wants to confess the Word by preaching it or by giving an account of it in court is in a very bad way on this earth. He is uncertain every hour and is in danger of being driven from his property, wife, and child while other folks are plentifully supplied and live in luxury and ease. But if we include in this view what is reserved for us and what we are there [in the world to come] to obtain, we ought certainly be very happy about the situation and far rather pity the poor, miserable world. For what difference does it make that people now step on us, intensely annoy and harm us? After all, we cannot be the losers. But if we do lose, we lose this mortal body. This, however, is losing no more than husks. Meanwhile the treasure remains ours; we shall plentifully receive again what we leave here, and much more besides, eternal, divine possessions."
I don't know - I just find it interesting. For some, the enormity of time serves as a way of trying to work around God, to replace Him. But for the faithful who simply trust in God and His salvation, the fact that our time here is brief is, well, not so bad. We've got plenty to look forward to, and it isn't bad.