Employing faith in extremely difficult situations seems irrational and contrary to what seems reasonable. Along these lines, consider Gideon and his minimized army in Judges 7:2 The Lord said to Gideon, “The people with you are too many for me to give the Midianites into their hand, lest Israel boast over me, saying, ‘My own hand has saved me.’ 3 Now therefore proclaim in the ears of the people, saying, ‘Whoever is fearful and trembling, let him return home and hurry away from Mount Gilead.’” Then 22,000 of the people returned, and 10,000 remained. 4 And the Lord said to Gideon, “The people are still too many. Take them down to the water, and I will test them for you there…”
You probably know the story—the number 10,000 is drastically reduced to 300 based on how they drank water from the stream and then it turns out that all the 300 soldiers had to do to defeat the massive Midianite army was blow some trumpets and smash some jars with torches inside because the enemy was already scared to death of them due to the dreams the Lord had given them.
Now think about how hard it would be for Gideon to trust in the Lord’s promise of victory in this case due to how irrational it is to the natural mind. You can imagine Gideon’s pleadings: “Lord, it’s typically better to bring more soldiers to a battle than less, if victory is the goal. Do you just want us to go out there and get slaughtered?” Well, as we know, victory was not the only intention of the Lord. He had to teach Gideon a lesson of complete reliance on him so that God alone would get the glory.
In other words, he needed to walk by faith in God, not by natural reasoning.