笃学不倦

Explanation: Duxue: concentrate studious; tired: tired. Concentrate studious, tireless. 　　Source: Ming Fang Xiaoru "and the degree of Zheng Shu Shu" under the Chun Ming Chi-liang, a gentleman of the device, and Duxue tireless, as the ancients also its Xi Yu, like it is growing meaning to the expectations fruit. "