Summary: Moses teaches followers of the Living God how to number their days; he does so with a Psalm.
“Lord, you have been our dwelling place
in all generations.
Before the mountains were brought forth,
or ever you had formed the earth and the world,
from everlasting to everlasting you are God.
“You return man to dust
and say, ‘Return, O children of man!’
For a thousand years in your sight
are but as yesterday when it is past,
or as a watch in the night.
“You sweep them away as with a flood; they are like a dream,
like grass that is renewed in the morning:
in the morning it flourishes and is renewed;
in the evening it fades and withers.
“For we are brought to an end by your anger;
by your wrath we are dismayed.
You have set our iniquities before you,
our secret sins in the light of your presence.
“For all our days pass away under your wrath;
we bring our years to an end like a sigh.
The years of our life are seventy,
or even by reason of strength eighty;
yet their span is but toil and trouble;
they are soon gone, and we fly away.
Who considers the power of your anger,
and your wrath according to the fear of you?
“So, teach us to number our days
that we may get a heart of wisdom.
Return, O LORD! How long?
Have pity on your servants!
Satisfy us in the morning with your steadfast love,
that we may rejoice and be glad all our days.
Make us glad for as many days as you have afflicted us,
and for as many years as we have seen evil.
Let your work be shown to your servants,
and your glorious power to their children.
Let the favor of the Lord our God be upon us,
and establish the work of our hands upon us;
yes, establish the work of our hands!” 
“Teach us to number our days.” I turned seventy years of age this past week. “Seventy” is just a number by which one can count the years of his pilgrimage. Accomplishments, the fulfilment of dreams is not measured by the number of circuits around the sun. A life can be defined by a hyphen. One day, should Christ tarry, each individual listening to this message will draw his or her final breath. After that final breath, a granite slab or a bronze plaque, will likely be placed in some prominent place as a memorial to the individual’s life; or perhaps it will be a line in a journal or an electronic entry on some data base. The plaque, or data entry, will have a date stating when that person began this life and a date stating when the last breath was drawn. Between these two dates will be a hyphen. Our days, and all that we did between the first and the last breath, will be reduced to a hyphen.
We are experts at counting our days, but the challenge of the Psalm is for us to live our days in such a way that they count. This particular Psalm is often read at funerals. It is appropriate to do so since the minds of the mourners are open to thinking of the brevity of life at such times. Listening to the Psalm, hearers are compelled to think of the impact we may have during the few days we live on this earth. This is a Psalm written by Moses—not someone we normally associate with the writing of the Psalms. It appears it was written near the end of his days, a time when he reflected on the brevity of life and weighed how to make the days count.