Percy Strickland gives us 8 ways to enter the fight to win using the story of David as a teenager using a single rock to force Goliath face down before God. Scripture (NRSV):
1 Samuel 17:17-51
17 Jesse said to his son David, ‘Take for your brothers an ephah of this parched grain and these ten loaves, and carry them quickly to the camp to your brothers; 18also take these ten cheeses to the commander of their thousand. See how your brothers fare, and bring some token from them.’
19 Now Saul, and they, and all the men of Israel, were in the valley of Elah, fighting with the Philistines. 20David rose early in the morning, left someone in charge of the sheep, took the provisions, and went as Jesse had commanded him. He came to the encampment as the army was going forth to the battle line, shouting the war cry. 21Israel and the Philistines drew up for battle, army against army. 22David left the things in charge of the keeper of the baggage, ran to the ranks, and went and greeted his brothers. 23As he talked with them, the champion, the Philistine of Gath, Goliath by name, came up out of the ranks of the Philistines, and spoke the same words as before. And David heard him.
24 All the Israelites, when they saw the man, fled from him and were very much afraid. 25The Israelites said, ‘Have you seen this man who has come up? Surely he has come up to defy Israel. The king will greatly enrich the man who kills him, and will give him his daughter and make his family free in Israel.’ 26David said to the men who stood by him, ‘What shall be done for the man who kills this Philistine, and takes away the reproach from Israel? For who is this uncircumcised Philistine that he should defy the armies of the living God?’ 27The people answered him in the same way, ‘So shall it be done for the man who kills him.’
28 His eldest brother Eliab heard him talking to the men; and Eliab’s anger was kindled against David. He said, ‘Why have you come down? With whom have you left those few sheep in the wilderness? I know your presumption and the evil of your heart; for you have come down just to see the battle.’ 29David said, ‘What have I done now? It was only a question.’ 30He turned away from him towards another and spoke in the same way; and the people answered him again as before.
31 When the words that David spoke were heard, they repeated them before Saul; and he sent for him. 32David said to Saul, ‘Let no one’s heart fail because of him; your servant will go and fight with this Philistine.’ 33Saul said to David, ‘You are not able to go against this Philistine to fight with him; for you are just a boy, and he has been a warrior from his youth.’ 34But David said to Saul, ‘Your servant used to keep sheep for his father; and whenever a lion or a bear came, and took a lamb from the flock, 35I went after it and struck it down, rescuing the lamb from its mouth; and if it turned against me, I would catch it by the jaw, strike it down, and kill it. 36Your servant has killed both lions and bears; and this uncircumcised Philistine shall be like one of them, since he has defied the armies of the living God.’ 37David said, ‘The Lord, who saved me from the paw of the lion and from the paw of the bear, will save me from the hand of this Philistine.’ So Saul said to David, ‘Go, and may the Lord be with you!’
38 Saul clothed David with his armour; he put a bronze helmet on his head and clothed him with a coat of mail. 39David strapped Saul’s sword over the armour, and he tried in vain to walk, for he was not used to them. Then David said to Saul, ‘I cannot walk with these; for I am not used to them.’ So David removed them. 40Then he took his staff in his hand, and chose five smooth stones from the wadi, and put them in his shepherd’s bag, in the pouch; his sling was in his hand, and he drew near to the Philistine.
41 The Philistine came on and drew near to David, with his shield-bearer in front of him. 42When the Philistine looked and saw David, he disdained him, for he was only a youth, ruddy and handsome in appearance. 43The Philistine said to David, ‘Am I a dog, that you come to me with sticks?’ And the Philistine cursed David by his gods. 44The Philistine said to David, ‘Come to me, and I will give your flesh to the birds of the air and to the wild animals of the field.’ 45But David said to the Philistine, ‘You come to me with sword and spear and 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. 46This very day the Lord will deliver you into my hand, and I will strike you down and cut off your head; and I will give the dead bodies of the Philistine army this very day to the birds of the air and to the wild animals of the earth, so that all the earth may know that there is a God in Israel, 47and that all this assembly may know that the Lord does not save by sword and spear; for the battle is the Lord’s and he will give you into our hand.’
48 When the Philistine drew nearer to meet David, David ran quickly towards the battle line to meet the Philistine. 49David put his hand in his bag, took out a stone, slung it, and struck the Philistine on his forehead; the stone sank into his forehead, and he fell face down on the ground.
50 So David prevailed over the Philistine with a sling and a stone, striking down the Philistine and killing him; there was no sword in David’s hand.Then David ran and stood over the Philistine; he grasped his sword, drew it out of its sheath, and killed him; then he cut off his head with it.
When the Philistines saw that their champion was dead, they fled.