What is the saying that begins with 'you have the knowledge to change things that you can and the wisdom of the things you can't'?

The Wording of the question paraphrases what is popularly known as the "Serenity Prayer;" the first stanza of a piece by Reinhold Niebuhr.

"God grant me the serenity to accept the things I cannot change,

Courage to change the things I can, and the Wisdom to know the difference."

Follow the link below for the entire piece.