《史记·八书·乐书》
礼若一昧谦抑，不自勉力进取，礼就会消亡，难以实行下去；乐只一昧盈满，不知自加抑制，就会流于放纵。
礼谦而不进，则销；乐盈而不反，则放。
If rituals are only about modesty and there is no self-encouragement or striving for progress, the rituals will wither away and become difficult to carry out; if music is only about fullness and there is no self-restraint, it will become indulgent.