Judges 7:4-7
4 But the Lord said to Gideon, “There are still too many men. Take them down to the water, and I will sift them for you there. If I say, ‘This one shall go with you,’ he shall go; but if I say, ‘This one shall not go with you,’ he shall not go.”
5 So Gideon took the men down to the water. There the Lord told him, “Separate those who lap the water with their tongues like a dog from those who kneel down to drink.”
6 Three hundred men lapped with their hands to their mouths. All the rest got down on their knees to drink.
7 The Lord said to Gideon, “With the three hundred men that lapped I will save you and give the Midianites into your hands. Let all the other men go, each to his own place.”