《汉书·传·匡张孔马传》
如果能考察《六艺》的要旨，人与天之间的关系和规律就可以得到并达到和谐，花草树木昆虫鸟兽就能够得到繁殖。这是永远不变的道理。
故审《六艺》之指，则天人之理可得而和，草木昆虫可得而育，此永永不易之道也。
If we can understand the essence of "Six Arts," the relationship and rules between humanity and heaven can be achieved and become harmonious, and flowers, plants, trees, insects, birds and beasts can reproduce. This is an eternal truth.