Sometimes the advice you give your children require an outside source to enforce your point. My eldest son has anxiety about making mistakes, in his studies, in sports, etc. This anxiety often keeps him from participating at a level that we know he is capable of, for fear of failing. Over and over we stress how mistakes help you learn, how proud we are of him, how much we respect effort - an though he trusts us, he struggles living it.
And then rereading Tom Robbins' Even Cowgirls get the Blues, I came across this passage, that made him smile, and think.
"So you think that you're a failure, do you? Well, you probably are. What's wrong with that? In the first place, if you've any sense at all you must have learned by now that we pay just as dearly for our triumphs as we do for our defeats. Go ahead and fail. But fail with wit, fail with grace, fail with style. A mediocre failure is as insufferable as a mediocre success. Embrace failure! Seek it out. Learn to love it. That may be the only way any of us will ever be free."