1Samuel 17:45 (ESV) Then David said to the Philistine, “You come to me with a sword and with a spear and with a javelin, but I come to you in the name of the LORD of hosts, the God of the armies of Israel, whom you have defied.
This is such a great account of God's power displayed through the faith of a young David before he became king. David had already been anointed by the prophet/judge Samuel in 1Samuel 16:13, "and the Spirit of the LORD rushed upon David from that day forward." If you aren't familiar with this Bible history, Goliath was a huge bully who challenged and taunted the Israelites. The Israelite soldiers were very afraid but David, who happened to be in the neighborhood to bring his brothers food, entered the battle front with confidence. Word got back to King Saul who reluctantly let David go out to face Goliath. Goliath was armed with a bronze helmet, full armor, a heavy javelin the size like a weaver's beam and also had a shield bearer before him. In contrast, David was armed with only his shepherd's staff, 5 smooth stones, his pouch, and a sling. Most importantly, he was filled with the Spirit of the LORD and armed with faith. David slung one stone which hit Goliath on the forehead and he fell to the ground. Then David took Goliath's sword and cut off his head! Wow!
David believed that God is Jehovah Sabaoth. King Saul and the whole army could only view the battle with physical eyes and assessed their military strength (and weakness) by physical measures. David on the other hand, was able to see with spiritual eyes which gave him the view of Someone much greater than Goliath. If you have time to meander through 1Samuel 16-17, please do. You will get a fuller picture of what's happening leading up to David facing Goliath in the name of Jehovah Sabaoth.
Another account to travel to is 2Kings 6:15-17 where the prophet Elisha was about to be attacked by a Syrian army and his servant was fearful. Elisha calmly told his servant, " 'those who are with us are more than those who are with them.' Then Elisha prayed and said, 'O Lord, please open his eyes that he may see.' So the Lord opened the eyes of the young man, and he saw, and behold, the mountain was full of horses and chariots of fire all around Elisha." We often only see and rely on our own physical resources. We forget that our spiritual Resource is far more powerful. Remember when facing a battle, Who is on your side.