In Arabic, we literally say:
The mistake made by a clever person is worth a thousand.
That is, is worth a thousand mistakes made by other people who are not clever. We use it to mean that people who are experienced are expected to be more careful and more immune to wrong-doing. And so if they do make mistakes, there's going to be major consequences and these mistakes will probably live on unforgiven. How can we nicely express this (rather extreme) idea in English?