佛祖統紀 29.13

29.13

述曰。六祖之後為二派。一曰青原思。思傳石頭遷。其下為曹洞雲門法眼。一曰南岳讓。讓傳馬祖。其下為臨濟溈仰。是為五家宗派。道一而已。而言五其宗者。由人世心病益多故治法屢為之變。一棒一喝一唱一和機用縱橫。殆不可以一律齊。猶應病與藥之義。汾陽作廣智歌明十五家宗風。是蓋示後人以遍參之意。可不知乎。

The Commentary states: After the Sixth Patriarch, two branches were formed. One was Qingyuan Xingsi; Si transmitted it to Shitou Xiqian, and beneath him came Caodong, Yunmen, and Fayan. The other was Nanyue Huairang; Rang transmitted it to Mazu Daoyi, and beneath him came Linji and Guiyang. These constitute the schools of the Five Houses. The Way is only one; that people speak of five schools is because the mind-sickness of the human world has grown increasingly manifold, so the methods of treatment have repeatedly shifted accordingly. A stick, a shout, a singing, a harmonious answering—their opportune functions are freely applied in all directions, so they can hardly be standardized by a single rule. This is just like the principle of administering medicine in response to the illness. Fenyang composed the Song of Guangzhi to clarify the lineages and styles of the fifteen houses; this was surely to indicate to later generations the intention of universally visiting teachers. Could one not know this?