The source for the adage isn't Einstein. The website Quote Investigator traced this quote, "A ship in harbor is safe, but that is not what ships are built for," to author John A. Shedd.

Signed Albert Einstein quote on sale for $65,000 Card stating ‘The greatest value of knowledge lies in knowledge itself’ is available for purchase online By Gavriel Fiske Follow ...

Thanks to the internet, Albert Einstein ... That's not to say that every single quote ascribed to Einstein on the internet is bogus, however. Take this statement, which has circulated online ...