維摩經玄疏 5.17

5.17

四、有師翻云善語教者，大聖大慈心，順理說法，故言善語。用悉檀赴機，化物順情，成行人入理，故云善語教也。

Fourth, some masters translate it as "teaching of good words": out of great compassion, the Great Sage preaches the Dharma in accord with principle, and therefore it is called good words. Using the siddhāntas to respond to capacities, transforming beings in accord with their sentiments, and enabling practitioners to enter principle, it is therefore called the teaching of good words.