Do not pray for easy lives. Pray to be stronger men.
Do not pray for tasks equal to your powers. Pray for powers equal to your tasks.
Then the doing of your work shall be no miracle. But you shall be a miracle.
Every day you shall wonder at yourself, at the richness of life which has come to you by the grace of God.
- Phillips Brooks
Wikipedia has some biographical information on Phillips Brooks.
On his weekly address on 14 February 2009, President Obama quoted President Kennedy with similar words (watch this weekly Presidential address on YouTube, quote happens at 4:00 to 4:15). One can assume Kennedy was paraphrasing Brooks, and in turn, Obama was paraphrasing Kennedy.
An easier life would not contribute to your growth, whereas becoming stronger would.
Connections: Brooks was a priest in Massachusetts. The Kennedy family was from the Massachusetts area. Obama sees in Kennedy a model for being President and a better American.
Also, Obama understands how people in the United States feel about the Kennedys and uses that connection (“This morning I’m reminded of words President Kennedy spoke..”) to elicit a certain kind of response. He does not quote Brooks; that connection does not have as much value as the Kennedy one.