維摩經玄疏 6.128

6.128

第四、正明判此經教相者，但如來經教，乃遍滿三千，元其正意，不出四種：一者，頓教；二者，漸教；三者，不定教；四者，祕密教。

Fourth, directly clarifying the classification of the characteristics of this sūtra's teaching: Although the Tathāgata's scriptural teachings fill the three-thousandfold [world system], examining their primary import, they do not exceed four kinds: first, the sudden teaching; second, the gradual teaching; third, the indeterminate teaching; fourth, the esoteric teaching.