意译: If you cannot live for yourself, how could you live for someone else? Only when you are happy, you will be able to bring happiness to others and to better help others.
If their existence do not have the value, how that does live for others, the happy camper can give others the true joy, only then may better help others .
If there is no value of your existence, how to exist for other people, only the happy people can give their own true happiness to others, and can better help others.