《易传·系辞传上·第十二章》
圣人见天下一切动作营为的众多，而观察它可以会而通之之道，以制定其经常的规范，订成三百八十四种动态的指规，又系以文辞，以断定它的吉凶，所以谓之 爻 。
圣人有以见天下之动，而观其会通，以行其典礼，系辞焉以断其吉凶，是故谓之爻。
The sage sees how myriads of actions and undertakings in the world are many, and he examines it for a way to understand them all together so as to establish their regular patterns, arranging three hundred and eighty-four kinds of dynamic indicators and again tying them to texts in order to determine auspiciousness or inauspiciousness; thus it is called lines.