I never got around to reading J K Rowling's Harvard commencement speech due to my serious lack of interest of the whole Harry Potter thing. I was a fool, then, because her speech is lovely. You can both read the text and watch the video online.
The knowledge that you have emerged wiser and stronger from setbacks means that you are, ever after, secure in your ability to survive. You will never truly know yourself, or the strength of your relationships, until both have been tested by adversity. Such knowledge is a true gift, for all that it is painfully won, and it has been worth more to me than any qualification I ever earned."