What is an ancient poem that describes people who do great things without hurting people?

A promise of a thousand dollars, a promise of a thousand dollars, I will live up to it.

If you don't trust me, your old friend will fail me. People, never speak out of turn, and never promise out of turn. Gentlemen break up when they disagree: loyal ministers serve the country, and their names are not correct. It means that a cultured person will not hurt others with ugly words when breaking up with others; Loyal ministers leave the country and do not deliberately beautify their reputation.