The lives of great men set an example for people, teaching them that they can make their lives "sublime," or lofty in thought and purpose, and then leave behind something worthwhile, such as noble deeds. In this manner, then, others can follow in their footprints:

 Lives of great men all remind us 
   We can make our lives sublime, 
And, departing, leave behind us 
   Footprints on the sands of time;

In his poem, Longfellow exhorts his fellowmen to live worthwhile lives with a strong heart for any fate. In this way, people set examples for those who follow, hopefully inspiring them in turn.

Let us, then, be up and doing,     With a heart for any fate;  Still achieving, still pursuing,     Learn to labor and to wait.

"The Psalm of Life" verses carry a strong and encouraging message to live life fully and with the idea that one's life serves as an example to those who come afterwards and may wish to follow those "footprints on the sands of time." Just as the Psalms of the Bible inspire, Longfellow's "A Psalm of Life" is meant to inspire those who read it to live better, more productive lives: "Learn to labor and to wait."