One wrong word, five hundred lifetimes as a wild fox.
In the Buddhist context, “severing someone’s wisdom life” refers to cutting off another person’s opportunity to attain enlightenment through wisdom by misleading, destroying the Buddha’s teachings, or hindering practice.
During the height of Tang Dynasty, Zen Buddhism flourished. When Zen Master Baizhang (749-814AD) gave dharma talks, a certain old man would come to listen. He usually left after the talk, but one day he remained.
Baizhang asked, “Who are you?”
The old man replied, “I’m not human. In the time of Buddha Kashyapa, I was also a practitioner, living on this mountain. Someone asked me, “Do those who practice with great devotion still fall into cause and effect?’” I replied, “They do not fall into cause and effect” (meaning a great practitioner is not bound by cause and effect). Because I answered incorrectly, I have been reborn as a fox for five hundred lifetimes. Now, please help me with the correct answer so I may be freed from this fox’s body.”
Baizhang said, “Please ask me the same question.”
The old man then asked, “Do those who practice with great devotion still fall into cause and effect?’”
Baizhang answered, “They are not ignorant of cause and effect.” (Meaning that devoted practitioners are also bound by the law of cause and effect, but they are fully aware of the reasons for their karmic retribution and accept with equanimity.)
Upon hearing this, the old man attained great realisation. He bowed to bid farewell to Baizhang, saying, “I am now freed from fox’s body. The body I left behind lies in the back mountain. I humbly request that you bury it according to the rites for a deceased monk.”
The next day, Baizhang led the monks to a large rock in the back mountain, where they found a dead black fox and cremated it according to the rites for a deceased monk.
Origin: Wu Deng Hui Yuan
#27 野狐禅
一字之差，五百生野狐身。
在佛教语境中，“断人慧命”指的是通过错误引导、破坏佛法或阻碍修行，从而断绝他人通过智慧获得解脱的机会。
在盛唐时期，禅宗盛行。百丈禅师（749-814年）每次说法，都有一位老人跟随大家听讲。有一天大众退去后，老人还没走。
百丈禅师问：“你是什么人？”
老人说：“我不是人。过去迦叶佛时，我也是个修行人，住在这座山上。有人问我：“大修行人还会落入因果吗？” 我当时回答：“不落因果”（意味着大修行人可以不受因果束缚）。因为这句错话，我做了五百生的野狐狸。现在请您告诉我正确的回答，让我脱离野狐身。”
百丈禅师说，“请问我同样的问题。”
老人于是问：“大修行人还会落入因果吗？”
百丈禅师回答：“不昧因果（是指大修行人还是会承受因果报应的，只不过他们清清楚楚知道自己所受报应的原因，因而坦然接受。）”
老人听后顿时大悟，向百丈禅师行礼告辞说：“我已经脱离野狐身，留下的尸身就在后山，恳请和尚依照对待去世僧人的礼仪来安葬我。”
第二天，百丈禅师带领僧众们在后山一块大岩石上，找到了一只已经死去的黑色大狐狸，便按照送亡僧的礼仪将它火化了。
出自《五灯会元》