Presumably God willingly gave Gideon the signs of the fleece because He knew the command He would give him to reduce his army would stretch his faith to its limit. The Israelite soldiers numbered only 32,000 (or 32 units, v. 3) while the Midianites and their allies fielded about 135,000 warriors (or 135 units, 8:10).
God revealed His purpose in reducing Israel's army clearly. He wanted everyone to recognize that the victory was His work rather than Israel's (v. 2).
"Judges 7:2 is one of the most important verses in the Bible for understanding God's principles of spiritual warfare. God is not interested in simply giving His people victory. He is concerned with teaching us trust. In fact, if our victories make us self-reliant, they are ultimately more disastrous than defeat."159
In the law Moses had said that the Israelites should not force the fearful to go into battle (Deut. 20:8). God reminded Gideon to give any who were afraid the opportunity to go home, which he did (v. 3). However the large number that deserted him, more than two out of three, must have shocked Gideon. Then God said that even the remaining 10,000 soldiers (or 10 units) were too many (v. 4).
The normal way to drink from a stream was to get down on one's hands and knees and put his mouth to the water. This is what most of the soldiers did. A smaller number simply remained standing or kneeled, reached down, dipped one hand into the water, and brought the water to their lips. God told Gideon that he should send the majority home and that He would deliver Israel with the 300 men who remained. That made the ratio of Midianite and Israelite soldiers 450 to one (assuming elephmeans "thousand"here). It is not clear whether God's test and choice were arbitrary having no other significance than that most people drank in one way and fewer in the other. Possibly God designed the test to distinguish the more alert soldiers from the less alert.160Getting down on all fours leaves one more vulnerable than if one remains upright while drinking. Another possibility is that God intended to identify the least likely to succeed, those who had so little self-confidence that they kept an eye out for the enemy while they drank.161
"I suggest that the lapping by the 300 like dogs symbolizes a lapping of the enemy's blood."162
The text does not enable us to understand God's motive certainly. Simple obedience is what He required.
Note that before God told Gideon to let the larger group of soldiers go home He gave him a promise that He would deliver Israel with the 300 remaining warriors. This promise undoubtedly encouraged Gideon's faith.
