Calque from Literary Chinese 病從口入，禍從口出／病从口入，祸从口出. <span class="searchmatch">病</span>(やまい)<span class="searchmatch">は</span><span class="searchmatch">口</span>(くち)<span class="searchmatch">より</span>入(い)り、<span class="searchmatch">禍</span>(わざわい)<span class="searchmatch">は</span><span class="searchmatch">口</span>(くち)<span class="searchmatch">より</span><span class="searchmatch">出</span>(い)ず • (yamai wa kuchi yori iri, wazawai wa kuchi yori izu) (idiomatic)...