1 Samuel 6:8-11

And take the ark of the LORD and place it on the cart and put in a box at its side the figures of gold, which you are returning to him as a guilt offering. Then send it off and let it go its way and watch. If it goes up on the way to its own land, to Beth-shemesh, then it is he who has done us this great harm, but if not, then we shall know that it is not his hand that struck us; it happened to us by coincidence.” The men did so, and took two milk cows and yoked them to the cart and shut up their calves at home. And they put the ark of the LORD on the cart and the box with the golden mice and the images of their tumors.