What is the meaning of 'to err is human'?

To err is to make a mistake. To make a mistake is human. Humans are not perfect. They make mistakes. To make a mistake is to be human. You are human, and you are prone to mistakes. You will make a mistake sometime in your life. Probably a lot more than one. If you make a mistake you are simply experiencing one of the things humans are prone to. To err is human; to forgive, divine. That's the whole of the quote from Alexander Pope.