Enid Blyton said this quote

You think if someone does a brave deed quite suddenly, then he or she could never do a mean one? You are wrong. We all have good and bad in us, and we have to strive all the time to make the good cancel out the bad. We can never be perfect - we all of us do mean or wrong things at times - but we can at least make amends by trying to cancel out the wrong by doing something worthy later on.