Could you point me in the direction of references to that? Sounds interesting.
Oh, goodness, it seems like forever since I read it. I would think it is in the book of Joshua, or perhaps the first book of Judges. Let me see what I can find...
I stand corrected, it was Gideon, not Joshua:
Judges 7:1 Then Jerubbaal, who is Gideon, and all the people that were with him, rose up early, and pitched beside the well of Harod: so that the host of the Midianites were on the north side of them, by the hill of Moreh, in the valley.
Judges 7:2 And the LORD said unto Gideon, The people that are with thee are too many for me to give the Midianites into their hands, lest Israel vaunt themselves against me, saying, Mine own hand hath saved me.
Judges 7:3 Now therefore go to, proclaim in the ears of the people, saying, Whosoever is fearful and afraid, let him return and depart early from mount Gilead. And there returned of the people twenty and two thousand; and there remained ten thousand.
Judges 7:4 And the LORD said unto Gideon, The people are yet too many; bring them down unto the water, and I will try them for thee there: and it shall be, that of whom I say unto thee, This shall go with thee, the same shall go with thee; and of whomsoever I say unto thee, This shall not go with thee, the same shall not go.
Judges 7:5 So he brought down the people unto the water: and the LORD said unto Gideon,
Every one that lappeth of the water with his tongue, as a dog lappeth, him shalt thou set by himself; likewise every one that boweth down upon his knees to drink.
Judges 7:6
And the number of them that lapped, putting their hand to their mouth, were three hundred men: but all the rest of the people bowed down upon their knees to drink water.
Judges 7:7
And the LORD said unto Gideon, By the three hundred men that lapped will I save you, and deliver the Midianites into thine hand: and let all the other people go every man unto his place.
The book continues of course, giving some details of the battles that followed.