菩薩瓔珞本業經 1.49

1.49

「佛子！八、入一切佛國中行故。所謂四化法：法辯、議辯、語辯、樂說辯。是四名慧性，照一切法無生，入第一義諦中行故。

"Buddha-son! Eighth is practicing within all buddha lands, that is to say, the four transformative methods: eloquence in dharmas, eloquence in meaning, eloquence in language, and eloquence in joyful exposition. These four are called the nature of wisdom, illuminating all phenomena as unarisen, because one practices within the ultimate truth.