The best example of psychological warfare from the Bible is seen in the experience of Gideon (Judges ch. 6-7). During this time, roughly around 1190 B.C., a large armed force of Midianites, Amalekites, and other foreign soldiers invaded Israel; so numerous were their forces that Judges 6:5 refers to them as “swarms of locusts.” While the Israelite army, led by Gideon, had initially had contained 32,000 men, the Lord saw fit to have Joshua dismiss all but three hundred of them, so as to clearly show how He would be the one to whom victory belonged, not to Israel. Needless to say, the odds of Gideon winning such a battle seemed rather slim. .
"So Gideon sent the rest of the Israelites to their tents but kept the three hundred, who took over the provisions and trumpets of the others." 1 "...'Watch me,' he told them. 'Follow my lead. When I get to the edge of the camp, do exactly as I do. When I and all who are with me blow our trumpets, then from all around the camp blow yours and shout, 'For the LORD and for Gideon.'' 1
At Gideon's word, they each broke their pot to reveal the torch and sounded on the horn. The Midianites woke up to the frightening sound and saw they were surrounded by lights in the darkness. Then "the LORD caused the men throughout the camp to turn on each other with their swords." 1 In the end, the great psychological battle stood as a total victory for the Israelites and a symbol of God's miraculous power. The idea was replicated when "less than 50 miles from the spot of Gideon's triumph--and 3,000 years later--another night attack took place. In 1918, during the First World War, a British brigade mounted a successful night raid on Turkish lines and, interestingly, also used deceptive noise and light."6
