俱舍論記 30.165

30.165

「於此方隅至成勝業」者，此即第三顯略勸學。方謂四方，隅謂四隅。於此無我理教方隅，我已略說，為開智者慧毒利門。如身少破，著少毒藥，須臾毒氣遍一身中為毒門。今造此論亦復如是，開少慧門，諸有智者能深悟入，如似毒門，名慧毒門。從喻為名。庶各隨己自力堪能，修三乘行。遍悟所知四諦深理，成諸勝業。

Regarding "In this direction and quarter … accomplish superior karma": this is the third: showing brevity and encouraging study. 'Direction' refers to the four directions; 'quarter' refers to the four intermediate corners. Regarding this direction and corner of the doctrine and teaching of selflessness, I have briefly explained it in order to open the sharp gate of wisdom-poison for the wise. Just as when a body has a small cut and a little poison is applied, within an instant the vapor of the poison permeates the whole body, serving as a gate of poison. Now, composing this treatise is also like this: opening a small gate of wisdom, those who are wise can deeply awaken and enter it, just like a gate of poison; hence it is called the 'gate of wisdom-poison', named after the analogy. May each, according to their own ability and capacity, cultivate the practice of the three vehicles, completely awaken to the profound principle of the four noble truths of the knowable, and accomplish all superior actions.