大乘起信論裂網疏 3.110

3.110

粗中之粗，即第一執相應染也。本是二乘及信地菩薩之所遠離，今言凡夫智境者，信地名為內凡，與二乘人同其智斷，未入大乘聖位故。

"The coarsest among the coarse" is the first defilement, the attachment-associated defilement. It is fundamentally what those of the two vehicles and bodhisattvas on the stage of faith depart from. Here, stating that it is the cognitive sphere of ordinary beings' wisdom refers to the stage of faith being termed "internal ordinary beings," who share the same wisdom and severing as persons of the two vehicles, having not yet entered the noble stages of the Mahāyāna.