1 Samuel 6:1-3, 7, 9

The ark of the LORD was in the country of the Philistines seven months. And the Philistines called for the priests and the diviners and said, “What shall we do with the ark of the LORD? Tell us with what we shall send it to its place.” They said, “If you send away the ark of the God of Israel, do not send it empty, but by all means return him a guilt offering. Then you will be healed, and it will be known to you why his hand does not turn away from you.”

Now then, take and prepare a new cart and two milk cows on which there has never come a yoke, and yoke the cows to the cart, but take their calves home, away from them.

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.”