法華義疏 1.68

1.68

四者、有無門者，當佛說經時具有六體但未立文，將入泥洹命使安之，結集法藏始標經首也。

Fourth, the section on presence and absence: When the Buddha preached the scripture, it possessed all six realities, but the text had not yet been set down; when he was about to enter nirvāṇa, he commanded that they be established, and when the Dharma Pitaka was compiled, they were first marked at the head of the scriptures.