The Psalmist reminds us of our incapability of achieving that which does not end in despair. It is only through God "that we may gain a wise heart."
Martin Luther in his Small Catechism tells us, "I believe that I cannot by my own understanding or effort believe in Jesus Christ my Lord, or come to him. But the Holy Spirit has called me through the Gospel, enlightened me with his gifts, and sanctified me and kept me in the true faith."
Our society is so driven to self-fulfillment that our memory fades and we forget that all we have and all we are comes from the Triune God. As we find in the first chapter of James, "Every generous act of giving, every perfect gift, is from above, coming down from the Father."
How is it with you?
Psalm 90:12-17 (NRSV)
12 So teach us to count our days that we may gain a wise heart.
13 Turn, O Lord! How long? Have compassion on your servants!
14 Satisfy us in the morning with your steadfast love, so that we may rejoice and be glad all our days.
15 Make us glad as many days as you have afflicted us, and as many years as we have seen evil.
16 Let your work be manifest to your servants, and your glorious power to their children.
17 Let the favor of the Lord our God be upon us, and prosper for us the work of our hands-- O prosper the work of our hands!