大般涅槃經集解 24.36

24.36

案僧亮曰：行有內外，偏行者遲、遍行者速。而聲聞，偏行外行也。所以然者，先有小心，須偏行以去之；凡夫不爾，是故速也。

Sengliang comments: Practices have internal and external; one-sided practice is slow, while pervasive practice is swift. The śrāvakas engage in one-sided practice and external practice. The reason for this is that they previously had petty minds and had to use one-sided practice to eliminate them; ordinary beings are not like this, so they are swift.