1 Samuel 6:12
And the kine took the straight way to the way of Beth-shemesh, and went along the highway, lowing as they went, and turned not aside to the right hand or to the left; and the lords of the Philistines went after them unto the border of Beth-shemesh.
The cows were unyoked and set free, with their calves shut up and left behind, separated from the mothers that were harnessed to carry the ark. Bearing the ark they took the straight way by the highway to Beth-shemesh, going directly forward without turning aside to the right hand or to the left. As they went they lowed for the calves they had been made to leave behind, yet kept to their forward course toward Beth-shemesh. They took that direct course to Beth-shemesh with the ark, where the Israelites afterward offered them to the Lord.
Angels accompanied the ark, and by unseen divine power directed the cows and brought the ark safely to the appointed place where it belonged. Their course was not one they would have taken of themselves, for unprompted mother cows would not have left their calves to go straight away from them. That unnatural straight going proved that the return of the ark was the work of God and was guided by His hand and presence, and not by chance.
The lords of the Philistines went after the ark and followed it as far as the border of Beth-shemesh. They dared not leave the sacred ark unattended, fearing that further calamity would come upon them if anything happened to it. The Lord Himself thus directed the cows carrying the ark straight to Beth-shemesh and delivered it where it belonged, showing that He can direct His sacred work to its proper place without human beings taking control of it.