Literature Reference: 我有中心乐，君无外事忙。—— 《池上早春即事招梦得》 I have joy in my heart, while you are not busy with external affairs. Source from 'Chishang Zao Chun Ji Shi Zhao Mengde'.
外: Exterior; the outside. It is the opposite of "inside" or "within."
事: Matters, affairs, and events.
Meaning: External affairs symbolize focus on the inner self, undisturbed by worldly matters.