Before you entrust an important job to someone with zero experience, maybe make sure the stakes aren’t too high.
(Narawanu kyou wa yomenu; “You can’t recite a Buddhist sutra you’ve never studied.”)
Complicated tasks are impossible to perform correctly without study and practice. No matter how much people may say that you should try, don’t expect to succeed at something you’ve never learned about or experienced.
We begin with the verb 習う (narau), “to learn,” or in this case “to memorize,” in imperfective form with negative suffix ず (zu) in prenominal form ぬ (nu). This allows it to attach to and describe the noun 経 (kyou), “sutra,” and the noun phrase as a whole is marked by the topic particle は (wa). (I’d say that here, the は carries an implicit contrast with sutras that have been studied.) And the phrase ends with the verb 読む (yomu), “to read (out loud),” in negative potential form.
Keep in mind that Buddhist sutras in Japan are not prayers as most Westerners would envision them. Many are still in Sanskrit, for one thing. And the Sanskrit text is represented phonetically with Chinese characters. And even in texts translated into Chinese, the pronunciation is often different from the on-yomi used in most contemporary Japanese pronunciation. It’s as if an American Catholic were trying to pray in Hebrew, but the Hebrew text was presented phonetically, untranslated, in Cyrillic. If you’re lucky you get a Latinate gloss showing you the pronunciation of the Cyrillic text, but it would be ridiculous to expect a random person off the street to read it accurately.
This saying is the な entry of the Osaka iroha karuta set.
This saying is nominally antonymous with 門前の小僧習わぬ経を読む, “The child before the gate reads sutras they never learned.” I would say that they’re really complementary, though; the child’s case may seem paradoxical, but this seeming contradiction actually serves to highlight the importance of one’s environment – the child at the temple gate learns the sutras by rote without evening noticing simply by hearing them recited all day every day.
(Kouhai-tachi ni shutsuba shite mitara umaku iku to omoimasu yo! to unagasaretemo, Nakata-san wa “Watashi mo narawanu kyou wa yomenu” to iitsudzukete, enryo shita.)
[The underclassmen tried to encourage Nakata, saying they thought things would go well if she tried out for the position. But she declined, repeatedly saying “I can’t do I job I never learned.”]