During the Three Kingdoms period, after Cao Cao had consolidated power in the north, a tripartite standoff formed with Liu Bei and Sun Quan. Cao Cao's son, Cao Pi, anxious to secure his position as successor, sought advice from Jia Xu on how to solidify his standing.

Jia Xu advised him, saying, "I wish for the General to extensively elevate his moral character, personally embody the virtues of a humble scholar, diligently work day and night, and always act in accordance with filial piety. That is all."

Cao Pi heeded his counsel, dedicated himself to arduous self-cultivation and refinement, and ultimately succeeded in ascending to the imperial throne.

This idiom, "深自砥砺," encapsulates the spirit of diligently tempering and refining oneself through continuous effort and discipline.