《文心雕龙·议对》
论祭祀，必须深悉礼仪；写战争，必须懂得军事；讲种田，首先要通晓农业；议断案，务须精通法律。
又郊祀必洞于礼，戎事必练于兵，佃谷先晓于农，断讼务精于律。
When discussing sacrifices, the rituals must be deeply understood; when writing about wars, military knowledge must be known; when talking about farming, the knowledge of agriculture must be understood first; when adjudicating cases, the law must be mastered.