Where do self-denial and self-restraint come from?

"Self-denial and self-surrender" comes from "Wang Han's Family Biography": "Emperor Xiaowen wants to build a platform and refuses to do it for a hundred dollars." It means to restrain and restrain yourself; Be strict with yourself. This also means that in the past, shops claimed that their prices were fair and they didn't make much money.

"Cautious independence" comes from the Book of Rites University: "This means that sincerity is in the middle and shape is outside, and a gentleman must be cautious about its independence." It means to be cautious when living alone, cautious when living alone without supervision, and consciously abide by various moral standards.

"Keeping the heart" comes from Tang Yuanzhen's poem "Watershed": "A gentleman is like water, drifting day and night. Those who keep their hearts well are also allied. " It means to guard one's mind; Refers to guarding one's inner light; Hold one's heart; Stick to one's will; Still patient.

The specific source of "Ming" has not been found.