From
曹植《
当欲游南山行》 (Cao Zhi, Three Kingdoms, early 3rd c.):
日月不同光,
昼夜各有宜 (Sun and moon do not share one light; day and night each has its own fitting time). The canonical companion line to
日月不同光 — the pair argues for recognizing each being's or time's proper role instead of forcing everything into one mold.