Man, oh man, I cannot believe my vacation—much less the summer—is over. Next week our daughter begins grade 4 and our twin sons start preschool. Just a week ago my wife and I celebrated our 11^th anniversary. And if I really want to think of how far life has come and gone, I need only recall that I’ve been out of high school for 23 years. Finished my undergrad 18 years ago. Received my Master’s degree 15 years ago. I mean, c’mon, this year I turn 41. Forgive the cliché, but it’s true (cue impressive Latin phrase!): tempus fugit. Or as we usually say it, “Time flies.” And, believe me, it does so even when you’re not having fun.

If most of you are like me, then most days you live as though your death is an eternity away. Continuing with the “time” image, we act as though we have “all the time in the world.” Whether the thought of our own death bothers us or not, dwelling on what the final date inscribed on our tombstone will be is likely not a regular routine. Moments occasionally come along when I realize that there is still much of the young boy and college student in me. I think more years  still lie ahead of me than behind. But as my wife likes to remind me, I am now middle-aged! In the U2 song from their album How to Dismantle an Atomic Bomb, “City of Blinding Lights,” Bono sings reflectively, “Time won’t leave me as I am/ Time won’t take the boy out of this man.” It’s funny how both things can be true, isn’t it?

Psalm 90 seems to have been written by someone perhaps reflecting on the realities of age and of mortality. Sounding a great deal like the Teacher of Ecclesiastes, the psalmist writes: “The days of our life are seventy years, or perhaps eighty, if we are strong; even then their span is only toil and trouble; they are soon gone, and we fly away.” There is a definite realism and honesty in the biblical text about the temporal limitations we all face.

But we don’t like to face these limitations in our culture. Surely the big business of cosmetic surgery attests loudly to this. Other signs of our desire to avoid age and our own eventual demise abound. Think of the woman who says, “I turn 35 again this year.” Or the man who dyes his graying temples. Or parents who try to live vicariously through their children. In our society, youth is god-like, a sign of strength and success. And of course our culture is not alone in wanting to prolong life. Think of the legend of the Fountain of Youth, a spring that supposedly restores the youth of anyone who drinks or bathes in its waters. Tales of such a fountain have been recounted across the world for thousands of years. According to an apocryphal combination of New World and Eurasian elements, Juan Ponce de León was searching for the Fountain of Youth when he traveled to what is now Florida in 1513. Imagine the money people would pay if such a fountain were ever found. Walmart would set up shop by the fountain overnight. Apple would design an app to use it.

Obviously, searching for some legendary fountain is not the way of dealing with our finitude. Thankfully, God in his wisdom offers us truth about how to think about this reality. Aware of his own unavoidable death, the writer of Psalm 90 brings this awareness to God in prayer: “So teach us to count our days that we may gain a wise heart.” I see at least two things to note here. First, God needs to give us a better grasp of our own mortality. Teach us, the Psalmist asks. More than that, the psalmist asks because he wants to live wisely. Knowing, therefore, that we only have so much time is understood as a prompt to wiser living.

Think of people who make so-called “bucket-lists.” Often those who make such lists are people who have been diagnosed with a terminal illness or who have in some other way been confronted by their own mortality. Having had the realization that they will really not live forever, such a list-maker thinks, “I better make a list of things that I want to do and should do before I die. This is my last chance.” Becoming more intimately aware that their days on this earth are numbered, such a person decides to use the time he or she has doing things they’ve put off. Being able to number our days rightly potentially rids each of us of the procrastinator within.

One other thing about what the psalmist is saying. He’s saying it all to God. This is prayer. Underlying his desire to have a more honest grasp of the length of his life is what the Bible calls a fear of the Lord. The Bible makes clear elsewhere that “the fear of the Lord is the beginning of wisdom” (Psalm 111:10). While meaning more, having a fear of the Lord at the very least means knowing that one’s life is ultimately in God’s hands. And not just this brief earthly sojourn. What happens to our life after we die is also in God’s hands. Wanting to live wisely, therefore, means wanting to live life—all of life, as much of it as we have—in relation to God. It means finding in God our very reason for living. “Lord,” the psalmist is saying, “help me to live for you in the time that you have given to me.”

Much of our culture tells us to do whatever we can to extend our stay on this blue-green planet in order to have more time to enjoy what we like, to do what we want to do, to live how we want to live. But the current of biblical wisdom runs in a considerably different direction. And Jesus, thankfully, describes it to us: “For whoever would save his life will lose it, but whoever loses his life for my sake will find it” (Matthew 16:25). Being able to count our days wisely in order to live wisely means knowing that we can never save our lives—much less add days or weeks or years to our calendar. Tempus fugit. Since this is so, we should make the prayer of Psalm 90 our own before it’s too late.