四分律行事鈔資持記 1.753

1.753

勸發中。唯言上品，故知中下非是正意；為顯上品，令知優劣。若下，《毘曇》所明：有一羅漢，戒是下品；年少比丘，却得上品，皆由最初發心有異。乃至者，始從凡夫，終至無學；歷諸階位，更不增長。或云：受體是定，隨行有增；或約作戒永定，無作通增，並具如後。

Under "Exhorting Aspiration": it speaks only of the superior grade; hence we know that the middle and lower are not the primary intention; they are mentioned to reveal the superior grade so that one may know the superior and inferior. From "If" onward is what is explained in the Abhidharma: there was an arhat whose precepts were of the lower grade, while a young bhikṣu, on the contrary, obtained the superior grade; this was entirely due to the difference in their initial aspiration of mind. "And so forth" means starting from ordinary people and ending with those beyond study; throughout all ranks and stages, there is no further increase. Or it is said: the reception-essence is fixed, but subsequent practice increases; or it is explained in terms of the manifest precept being permanently fixed, while the unmanifest generally increases—both are fully as explained below.