瑜伽師地論略纂 6.81

6.81

復有四清淨道：一、「非功用根圓滿」等者，此即四行跡，謂苦遲通、苦速通、樂遲通、樂速通。如次配之。鈍根名遲，利根名速。未至及無色地名苦，定慧一偏故；根本靜慮名樂，雙道轉故。雖未至地名有喜樂，未圓滿故，但名為苦。　「功用根」者，謂練根也。然〈菩薩地〉依凡聖差別，與此不同，及至〈聲聞地〉當辨。

Furthermore, there are four pure paths: First, "the perfection of faculties without effort" and so forth: these are the four modes of progress, namely, painful progress with sluggish higher knowledge, painful progress with swift higher knowledge, pleasant progress with sluggish higher knowledge, and pleasant progress with swift higher knowledge. They correspond respectively in this order. Dull faculties are called sluggish; sharp faculties are called swift. The access stage (anāgamya) and the formless realm are called painful, because samādhi and prajñā are one-sided; the fundamental dhyānas are called pleasant, because both paths operate together. Although the access stage is said to have joy and pleasure, because it is not complete it is merely called painful. "Faculties with effort" refers to training the faculties. However, in the "Bodhisattvabhūmi" this is distinguished according to ordinary beings and āryas, which differs from this, and it will be distinguished when reaching the "Śrāvakabhūmi".