Values – principles or standards of behaviour; one’s judgement of what is important in life. (Oxford Dictionaries)
Values are important because you’re more likely to succeed if you believe in what it is you’re doing.
Principles – a fundamental truth or proposition that serves as the foundation for a system of belief or behaviour or for a chain of reasoning. (Oxford Dictionaries)
Principles are important because they remove ambiguity when making decisions and help people to understand where they stand within an organisation.