1，天行健，君子以自强不息。—《周易》 This sentence is famous among Chinese, and it encourages people to keep vitality by being positive and active. And it comprises the concept of self-reliance. 2，躬自厚而薄责于人，则远怨矣。—《论语》 This byword is not that well-known in China, but it claims the danger of selfish clearly. It means that if you only know how to enrich yourself and refuse to share, the complaint will accumulate from somewhere. 3，满招损，谦受益。—《大禹谟》 This old saying has been regarded as a proverb in China. It means that the complacence would make you entail some lose and you will get the benefits originated from your the humility unexpectedly. My English is not affluent, so it may be inconvenient for you to understand me. Hope that these sayings can help you.

In pholosophical context, the firt of your phrase will be 实证的；I'm not sure about the other 2, they do not come so often in my reading. Would you paste the full sentences where they appear?

Be positive. 保持乐观 Be selfless.保持无私 Be humble.保持谦虚