唯識二十論述記 1.18

1.18

答：彼《三十論》廣顯自宗，此中《二十》廣破外難，雖俱明唯識，二論有別也。又彼《三十》廣顯正義，此中《二十》廣釋外難。又彼《三十》天親後造，有頌無釋，此中《二十》天親先作，有頌有釋。又明唯識，二論雖同，開設千門，令隨一入，故須別造二部論也。又妙理幽玄，丁寧始顯，宗趣雖一，二論重明，是謂二論緣起各別。

Answer: That Triṃśikā broadly reveals its own tenet, whereas the present Viṃśikā broadly refutes external objections; although both clarify vijñapti-mātra, the two treatises differ. Furthermore, that Triṃśikā broadly reveals the correct doctrine, whereas the present Viṃśikā broadly resolves external objections. Furthermore, that Triṃśikā was composed later by Vasubandhu and has verses without commentary, whereas the present Viṃśikā was composed earlier by Vasubandhu and has both verses and commentary. Furthermore, although the two treatises are identical in clarifying vijñapti-mātra, a thousand gates are opened to allow entry by any one of them; hence the two treatises had to be composed separately. Moreover, the marvelous principle is abstruse and profound, and becomes apparent only through repeated instruction; although the tenet and purport are one, the two treatises clarify it anew. This is why the occasions for the two treatises are distinct.