In the village of Hani, Nakata district, Awa province, there was a woman whose surname was Imbe no obito (Her name was Tayasuko.) In the reign of Emperor Shirakabe, she was copying the Hoke-kyō at Sonoyama-dera in Oe district when Imbe no muraji Itaya of the same district spoke ill of her, pointing out her mistakes. Immediately he was inflicted with a twisted mouth and a distorted face, which never returned to their normal state.
The Hoke-kyō says: “If you speak ill of a devotee of this scripture, none of your organs will work well, and you will be dwarfed, ugly, feeble minded, blind, deaf, and hunchbacked.” Speaking to the same effect, it also says: “If you reveal the mistakes of a devotee of this scripture, you will contract leprosy in this world, whether what you say is true or not.” Therefore, be reverent and have faith in the Hoke-kyō. Praise its power. Do not speak ill of others’ faults, for you may incur a great disaster if you do. (Page 248-249)
Miraculous Stories from the Japanese Buddhist Tradition (Nihon ryōiki)