Make a new cart, &c. It was in honour of the ark that they employed nothing about it that had ever served for any other use. And there was another reason for choosing such kine as are here mentioned; that it might be more manifest that they were led by the God of Israel, if they went directly into his country. For untamed heifers are apt to run back, or to wander, and keep no certain and constant paths, as oxen accustomed to the yoke do; and therefore were very unlikely to keep the direct road to the land of Israel. And the taking their calves from them would excite natural affection in them, and cause them rather to return home to their calves than to go into a strange country.
Related Commentaries of 1 Samuel 6:7
1 Samuel 6:7
7 Now therefore make a new cart, and take two milch kine, on which there hath come no yoke, and tie the kine to the cart, and bring their calves home from them: