說無垢稱經疏 4.524

4.524

贊曰：此第三問。其病體者，四大乖違，令眾苦逼。於此四界，何界病耶？界者，性也因也類也。四大體類說為色因，故名為界。

Commentary: This is the third question. Regarding the substance of the illness, the disharmony of the four great elements oppresses one with manifold sufferings. Among these four elements, the illness of which element is it? 'Element' (dhātu) means nature, cause, or category. The substance and categories of the four great elements are spoken of as the causes of form, and are therefore called 'elements.'