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. - Free Bible Online

      5. bring them down unto the water--When the wandering people in Asia, on a journey or in haste, come to water, they do not stoop down with deliberation on their knees, but only bend forward as much as is necessary to bring their hand in contact with the stream, and throw it up with rapidity, and at the same time such address, that they do not drop a particle. The Israelites, it seems, were acquainted with the practice; and those who adopted it on this occasion were selected as fit for a work that required expedition. The rest were dismissed according to the divine direction.

JFB.