If you contribute to other peoples happiness, you will find the true meaning of life. The key point is to have a genuine sense of universal responsibility
An enemy is indeed a precious teacher.
Live a good, honourable life. Then when you get older and look back, you'll be able to enjoy it a second time.
Religious belief is not a precondition either of ethical conduct or of happiness.
In our concern for others, we worry less about ourselves.
Without the human community one single human being cannot survive.