首楞嚴義疏注經 4.463

4.463

世、出世智所知之境，唯舌詮顯。能詮言句猶可分限，所詮理趣莫能盡極，故千二百。

The objects known by mundane and supramundane wisdom are expounded and revealed solely by the tongue. The words and sentences capable of expressing still have limits, but the principle and import expressed can never be exhausted; hence it is one thousand two hundred.