起信論疏筆削記 1.13

1.13

序者，敘也。謂敘述一論之大意故。又訓緒也，此文即製疏入作之端緒故。

'Preface' (*xu*) means to narrate (*xu*); that is, because it narrates the general meaning of the whole treatise. It is also glossed as a clue or beginning (*xu*), because this text is the starting clue for composing the commentary and entering into the work.