宜善護持 “Guard it well.”

宜 yí should
善 shàn good, appropriate
護 hù protect, safeguard, defend
持 chí hold, retain (as in dharani)

Found in “The Collected Works of Korean Buddhism: Gongan Collections 1”
Specifically in Case 324, “Yaoshan’s Three Vehicles”

Chan master Weiyan1029 of Mt. Yao in Fengzhou asked Shitou (Xiqian), “I have a rough understanding of the three vehicles and the twelve divisions of the teaching, but I once heard of the southern teaching of directly pointing at the mind of people, seeing into one’s own nature, and attaining buddhahood and do not truly comprehend it yet. I beseech your reverence to compassionately offer guidance.” Shitou said, “It is so will not do and it is not so will not do. It is and it is not so – neither will do. What then?” The master immersed himself in deep thought. Shitou said, “You have no karmic connection here.” In Jiangxi there is Great master Mazu (Daoyi), you should go to him. He will certainly explain it for you.” The master went there and asked what he asked before. Mazu said, “On certain occasions I say, one must raise his eyebrows and blink his eyes. On other occasions I do not say, one must not raise his eyebrows and blink his eyes. To tell a student on certain occasions that he must raise his eyebrows and blink his eyes will do and to tell him on other occasions to raise his eyebrows and blink his eyes will not do.” The master thereupon had an awakening and made obeisance. Mazu said, “What truth have you seen?” The master said, “When I was at Shitou’s it was as if I were a mosquito (trying to draw blood from) an iron ox.” The master said, “You are indeed at such a state. Guard it well.”

灃州藥山, 惟儼禪師問石頭,“三乘十二分敎, 某甲粗知, 嘗聞南方直指人心, 見性
成佛, 實未明了. 伏望和尙慈悲指示.”頭云,“恁麽也不得, 不恁麽也不得, 恁麽不
恁麽摠不得. 汝作麽生?”師佇思, 頭云,“子因緣不在此. 江西有馬大師, 子往彼
去, 應爲子說.”師至彼, 准前請問. 馬祖云,“我, 有時, 敎伊揚眉瞬目;有時, 不敎
伊揚眉瞬目. 有時, 敎伊揚眉瞬目者, 是;有時, 敎伊揚眉瞬目者, 不是.”師於是有
省, 便禮拜. 祖曰,“子見箇什麽道理?”師云,“某甲, 在石頭時, 如蚊子上鐵牛.”祖
曰,“汝旣如是, 宜善護持.”