swear on a stack of Bibles

Idioms  

1. Promise solemnly that what one is about to say is true, as in I swear on a stack of Bibles that I had nothing to do with his dropping out. This term alludes to the practice of placing one's hand on a sacred object while taking an oath, which dates from the mid-10th century. It is still followed in courts of law where a witness being sworn to tell the truth places a hand on the Bible. [Mid-1800s]

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Example Sentences

Think of expressions like “I swear on a stack of Bibles” and “as God is my witness.”

From Time

Of course, Joe Mondragon would swear on a stack of Bibles, if you asked him to, that he had awakened at least twenty times in the middle of the night these past five years and heard both the walking bass and the treble runs at the same time carrying across on the clear black air to his startled ears.

From Literature

“Noah, it wasn’t me. I swear on a stack of Bibles.”

From Literature

Why, Sherlock, if it weren’t for your super intellect and your remarkable powers of observation, which no one could mistake, I’d swear on a stack of Bibles that you were Elizabeth Harley of Lakeview Hall, otherwise known to her intimates as Lunch-Box Lizz.

From Project Gutenberg

Athwart its picturesque pages marches a numerous company of bold and imaginative liars, every man of them ready to swear on a stack of Bibles that his is the only true, unvarnished version of the events which caused the gold and jewels and plate to be hidden.

From Project Gutenberg