When an unexplainable occurrence (aka miracle) happens causing/allowing one to save money.
Examples of this phenomenon are plentiful. Finding a coupon right before you're about to buy something. Discovering a discount at the register for something you're about to buy. Noticing that you have an extra $100 in savings you forgot about. Finding an extra $5 in your purse you never knew was there. Tampax being put on sale during the week you just so happened to start your period. The list goes on and on.....
"Honey, remember that resturant we're going to on Friday? I just got a coupon for it in the mail! It's Divine Jewish Intervention!"
"I went to the store expecting to pay $100 for those shoes but Divine Jewish Intervention caused them to only ring up for $80!"