Wiktionary
bible thumper
n. (context pejorative English) a Christian fundamentalist, or an over-zealous evangelical Christian.
Usage examples of "bible thumper".
That's where Brother Billy, a white preacher from the Deep South and, I should mention, a real Bible thumper, led a little church in a Harlem storefront.
But this Bible thumper - It was six weeks after we moved into our new house.