乐于助人是一种美德，是一种社会责任感。在我们的日常生活中，如果我们能够乐于助人，那么我们就能够为他人创造更多的幸福和快乐。以下是一些经典的英文句子，这些句子都表达了乐于助人的重要性和价值。

1. 'No act of kindness, no matter how small, is ever wasted.' - Aesop

2. 'The purpose of human life is to serve and to show compassion and the will to help others.' - Albert Schweitzer

3. 'We rise by lifting others.' - Robert Ingersoll

4. 'The greatest good you can do for another is not just to share your riches but to reveal to him his own.' - Benjamin Disraeli

5. 'Help others achieve their dreams and you will achieve yours.' - Les Brown

6. 'The best way to find yourself is to lose yourself in the service of others.' - Mahatma Gandhi

7. 'The purpose of life is not to be happy. It is to be useful, to be honorable, to be compassionate, to have it make some difference that you have lived and lived well.' - Ralph Waldo Emerson

8. 'One of the most important things you can do on this earth is to let people know they are not alone.' - Shannon L. Alder

这些句子都鼓励我们去帮助他人，去做有意义的事情，去创造价值。如果我们每个人都能够在日常生活中多做一些善事，那么我们的社会将会变得更加美好和和谐。