A Prayer of Moses the man of God. LORD, You have been our dwelling place in all generations.  2 Before the mountains were brought forth, Or ever You had formed the earth and the world, Even from everlasting to everlasting, You are God.  3 You turn man to destruction, And say, "Return, O children of men."  4 For a thousand years in Your sight Are like yesterday when it is past, And like a watch in the night.  5 You carry them away like a flood; They are like a sleep. In the morning they are like grass which grows up:  6 In the morning it flourishes and grows up; In the evening it is cut down and withers.  7 For we have been consumed by Your anger, And by Your wrath we are terrified.  8 You have set our iniquities before You, Our secret sins in the light of Your countenance.  9 For all our days have passed away in Your wrath; We finish our years like a sigh.  10 The days of our lives are seventy years; And if by reason of strength they are eighty years, Yet their boast is only labor and sorrow; For it is soon cut off, and we fly away.  11 Who knows the power of Your anger? For as the fear of You, so is Your wrath.  12 So teach us to number our days, That we may gain a heart of wisdom.  13 Return, O LORD! How long? And have compassion on Your servants.  14 Oh, satisfy us early with Your mercy, That we may rejoice and be glad all our days!  15 Make us glad according to the days in which You have afflicted us, The years in which we have seen evil.  16 Let Your work appear to Your servants, And Your glory to their children.  17 And let the beauty of the LORD our God be upon us, And establish the work of our hands for us; Yes, establish the work of our hands. 

This is the rare Psalm, in part because of who it's author is.  This is "a prayer of Moses."  That's right, the same Moses who went on Mt. Sinai and received God's Law for the children of Israel.  The same Moses who led the children of Israel through the wilderness for forty years.  

So what did Moses pray about?  The first half of the Psalm is a reminder of what earthly existence is like because of sin.  God turns man toward destruction, not out of spite, but in order to call us to repentance, saying "Return, O children of men."  We think a thousand years is forever, but a thousand years to God are nothing but a watch in the night, carried away like a flood.  The years are like grass that lasts a short time.  And when it comes to our sins, we are terrified and consumed by the wrath of God becuase we know that He sees all, that even our secret sins that we hide from everyone else are revealed in the light of His face.  And there's a penalty for that:  because we sin, we die.  If we live to seventy or eighty, we've had a pretty full life--and yet even then it's a life of labor and sorrow, soon cut off.  The first half of Moses' prayer is a confession of our sin and unworthiness.  

Yet in the first half Moses asks God to teach us something:  to number our days rightly, so that we may gain a heart of wisdom.  Everything that Moses confesses to God--these are also things we need to realize for ourselves.  That God's idea of time isn't our idea of time; that our lives are relatively short; that earthly life does come to an end.  We are to understand these things for ourselves and act accordingly--joining Moses in His prayer.    

In the second half, Moses prays for God's blessings, given the realities that we sinners face.  He asks the Lord to return and have compassion on us, to have mercy on us.  Compassion and mercy are related:  compassion is the desire to help those in need and mercy is to give help to those who don't deserve it.  Surely we don't deserve God's help; we've put ourselves under God's wrath by our own desires and actions.  Yet we can ask for and count on the Lord's love--because time and again He has demonstrated His love for us in Christ.  In the selfless compassion of Jesus that caused Him to take our sins on Himself and pay for them with His own life.

In connection with the saving work of God, Moses prays that God's work and His glory would appear to His servants and their children.  God's work--all of it from creation to redemption and to our own sanctification--is revealed to every one of us in the pages of the Bible.  When we open up that book, the Lord makes us glad, fills us with joy, and establishes the work of our hands.