孜孜不怠

Explanation: Diligent efforts, not slack. 　　Source: "Han-ping when the Biography" ordered the Chinese and this holy king, two hundred years following the body bearing industry, diligently not relent, the government had cleared carry on. " 　　Examples: Chen Tai prior three decades, watching his Yanjie alienation, ~, lower levels were even worse unreasonable. ★ Sima Guang Song, "Mirror" volume two hundred and eighty third