《文心雕龙·明诗》
所以总观历代的诗歌，其发展变化的情况是可以看得很清楚的。归纳一下它们相同和相异的特色，就可以看出诗歌创作的要点了。
故铺观列代，而情变之数可监；撮举同异，而纲领之要可明矣。
Therefore, by examining the poetry of each dynasty, the changing trends of its development can be clearly seen. By summarizing their common and different characteristics, the key points of poetry creation can be identified.