Searching for a supposed Robert F. Kennedy quote.

Hi all. I'm searching for a lengthy quote, perhaps a paragraph from a speech, which I think is attributed to RFK. It is best summarized as follows, "At the end of your life people will judge you, but you will ultimately come to judge yourself, not in what you've achieved, but in how you've used your talents and abilities to serve your fellow man."

Can anyone help me identify whether this was actually written/spoken by RFK, and if so, where it is from? Or, if not by RFK, who should I attribute this to?

Thanks a million!