教堂是教徒們進行宗教活動的地方，沒有人在這里吃東西，自然也不會有食品櫥。所以老鼠想在教堂里找吃的東西，根本是枉費心機。連吃的東西都沒有，教堂里的老鼠當(dāng)然是非常窮的。所以，(as) poor as a church mouse 意思就是“窮得像教堂里的老鼠，一貧如洗。”(having or earning barely enough money for one's needs)

“一文不名；一貧如洗；窮困不堪”還可以說成as poor as Lazarus.“窮得像拉撒路一樣。”它源自《圣經(jīng)•新約•路加福音》第16章關(guān)于拉撒路的故事。拉撒路是耶穌講的故事里的一個乞丐的名字。后來在西方語言中成為窮人或貧病交加的乞丐的同義語。

例如：

You want to borrow money from him? He is as poor as a church mouse.
你想從他那里借錢？他可是一貧如洗。

Mr. Li is now one of the richest men in town. Nobody could imagine that he was as poor as a church mouse when he first came to Hong Kong.
如今李先生是香港的巨富了。但沒有人會想到，他初到香港時，只是個一文不名的窮小子。