I Samuel 6:8-11

Then take the ark of the LORD and set it on the cart; and put the articles of gold which you are returning to Him as a trespass offering in a chest by its side. Then send it away, and let it go. And watch: if it goes up the road to its own territory, to Beth Shemesh, then He has done us this great evil. But if not, then we shall know that it is not His hand that struck us—it happened to us by chance.” Then the men did so; they took two milk cows and hitched them to the cart, and shut up their calves at home. And they set the ark of the LORD on the cart, and the chest with the gold rats and the images of their tumors.