1 Samuel 6:9

It was a chance that happened to us. — The priests and diviners were not certain whether the plague had been sent by the offended God of Israel or had visited Philistia in the ordinary course of nature. This strange experiment would satisfy the minds of the Philistine people. If the cows, contrary to their expectation, kept on the road to Bethshemesh, this would be a sign that they were driven and guided by a Divine power, and it would be clear to all that the Ark was a dangerous possession, and that they were well rid of it. They would be assured then that the scourge they were suffering from came from the angry Israelite Deity. If, on the other hand, the animals, left to themselves, returned to their own stalls, which, evidently, the diviners expected would be the case — then the Philistines might safely retain the Ark, being confident that their late sufferings were simply the results of natural causes. It will be remembered (1 Samuel 6:7) that these were milch cows, whose calves were shut up in the stall. The diviners felt quite sure that the cows, left to their own instincts, would, unless driven by some Divine power, come back to their young ones in the stall. What the priests and diviners advised was done, and the next two verses (10 and 11) relate how the restoration of the Ark was carried out in the way prescribed above.