A sly sister was wanting to test her beau's newly-acquired love of Jehovah and all things spiritual. So she says one day, "I'm sick of all of this field service. I say we quit!" and she hurls her bookbag into the lake. He says, "Oh thank God! I only did this because you did!" He follows suit and tosses his bag.
She now knows he isn't a True Christian(tm) so she breaks it off with him.
(And goes on to marry an elder that beats her, and is also a pedophile. Though I don't think that part is generally mentioned!)
Dave