妙法蓮華經玄贊 7.106

7.106

論說能滋之法以顯所喻，故以雨喻為名。經取能喻之體以破彼疑，故標藥草。倒者以乘無別為病，破者以機有別為破，故假所潤藥草以況所滋根性，由此不標雨為譬喻，亦不雙舉雨草二性為品。

The Treatise speaks of that which is capable of moistening in order to reveal what is illustrated; hence it takes the parable of rain as its name. The sūtra takes the substance capable of serving as a parable to shatter their doubts; hence it designates medicinal herbs. The error of the deluded lies in regarding the vehicles as having no distinction; the refutation lies in refuting it through the differences in capacity. Therefore, it employs the moistened medicinal herbs as an analogy for the capacities and natures that are nourished; for this reason, it does not designate rain as the parable, nor does it jointly cite the dual natures of rain and herbs for the chapter.