Who said "Be a master of your craft. Know what you are doing."?

This quote is attributed to Jack Ma.

Be a master of your craft. Know what you are doing. - Jack Ma

"Be a master of your craft. Know what you are doing."

Jack Ma

E-commerce Founder Chinese Born 1964 (age 62)

"Today is hard, tomorrow will be worse, but the day after tomorrow will be sunshine."

"Opportunities lie in the place where the complaints are."

"We are not here to work for money, we are here to realize our dreams."

"If you don't give up, you still have a chance."