Strength is happiness.

Buddhism Day by Day

Wisdom for Modern Life by Daisaku Ikeda
Saturday, January 12, 2013:

 

Strength is happiness. Strength is itself victory. In weakness and cowardice there is no happiness. When you wage a struggle, you might win or you might lose. But regardless of the short-term outcome, the very fact of your continuing to struggle is proof of your victory as a human being. A strong spirit, strong faith and strong prayer—developing these is victory and the world of Buddhahood.