《管子·匡君小匡》
因此，夜间作战声音相闻，就可以不乱；白天作战，眼睛一看，就可以相识。欢欣的情谊足以互相殉死。所以，用来防守则阵地巩固，用来战争则取得胜利。
是故夜战其声相闻，足以无乱；昼战其目相见，足以相识；欢欣足以相死，是故以守则固，以战则胜。
Therefore, for night operations they could hear each other's voices and maintain order; for daytime operations, seeing each other they could recognize each other. Such joyous friendliness was enough for mutual sacrifice. Therefore, they could remain firm when defending a position, and victorious when waging war.