24 hours per day x 365 days per year = 8,760 hours per year
At almost 30 years old I've used up the overwhelming majority of the 262,800 hours that add up to 30 years.
At 70 years old a person will have lived 613,200 hours.
At 100 years old a person will have lived 876,000 hours.
What are you doing with the hours you are given? You are only given so many. The really tricky part is that you will most likely never know when your hours will come to an end.
You and I have very limited time in which to honor and glorify God in a unique way. I believe that we will be able to honor and glorify God, as we live on this earth, in ways that we will not be able to in eternity. For instance, in eternity there will be no sin, there will be no battles with sin, there will be no intense battles with suffering, and here these things abound. Therefore we are in a position to be able to honor and glorify God with our lives in ways that are unique to the time that we are given to live on the earth.
The sand in the hour glass is constantly falling. Some would even argue that it continues to fall at a faster rate. What are you and I doing with these hours we've been given, these grains of sand slipping through the hour glass.
Piper's lightly edited version of the old catechism phrase is helpful here: The chief end of man is to glorify God by enjoying Him forever.
Are our hours being spent glorifying and enjoying Him, or ourselves? God has had much to say in the Scriptures about stewardship and faithfulness. I'm quite certain that this stewardship and faithfulness also has to do with our time.