שמואל א, פרק ו׳, פסוק י׳

A deliberate test is set in motion to challenge the laws of nature and determine the true influence of the Ark of God. The men orchestrate this by hitching two nursing cows to a cart, while intentionally leaving their calves—their young offspring [ביאור שטיינזלץ]—behind.

The primary approach among commentators is that the calves are actively captured and locked securely inside a house. This strict confinement is not a random detail, but the very core of the experiment. Naturally, nursing cows possess a powerful maternal drive and will instinctively turn back to find their young. Shutting the calves away ensures a definitive outcome for the test. If the cows still pull the cart forward, moving away from their confined calves, it provides undeniable proof that the power of the Ark is guiding their path, completely overriding their deepest natural instincts [רד״ק].