As you intend to write on this subject, seeing the story as written with particular acuity in the book "Patriarchs and Prophets" (1890) may be of considerable interest to you. The following is excerpted from pages 644-648.
David and Goliath
When war was declared by Israel against the Philistines, three of the sons of Jesse joined the army under Saul; but David remained at home. After a time, however, he went to visit the camp of Saul. By his father's direction he was to carry a message and a gift to his elder brothers and to learn if they were still in safety and health. But, unknown to Jesse, the youthful shepherd had been entrusted with a higher mission. The armies of Israel were in peril, and David had been directed by an angel to save his people.
As David drew near to the army, he heard the sound of commotion, as if an engagement was about to begin. And “the host was going forth to the fight, and shouted for the battle.” Israel and the Philistines were drawn up in array, army against army. David ran to the army, and came and saluted his brothers. While he was talking with them, Goliath, the champion of the Philistines, came forth, and with insulting language defied Israel and challenged them to provide a man from their ranks who would meet him in single combat. He repeated his challenge, and when David saw that all Israel were filled with fear, and learned that the Philistine's defiance was hurled at them day after day, without arousing a champion to silence the boaster, his spirit was stirred within him. He was fired with zeal to preserve the honor of the living God and the credit of His people.
The armies of Israel were depressed. Their courage failed. They said one to another, “Have ye seen this man that is come up? surely to defy Israel is he come up.” In shame and indignation, David exclaimed, “Who is this uncircumcised Philistine, that he should defy the armies of the living God?”
Eliab, David's eldest brother, when he heard these words, knew well the feelings that were stirring the young man's soul. Even as a shepherd, David had manifested daring, courage, and strength but rarely witnessed; and the mysterious visit of Samuel to their father's house, and his silent departure, had awakened in the minds of the brothers suspicions of the real object of his visit. Their jealousy had been aroused as they saw David honored above them, and they did not regard him with the respect and love due to his integrity and brotherly tenderness. They looked upon him as merely a stripling shepherd, and now the question which he asked was regarded by Eliab as a censure upon his own cowardice in making no attempt to silence the giant of the Philistines. The elder brother exclaimed angrily, “Why camest thou down hither? and with whom hast thou left those few sheep in the wilderness? I know thy pride, and the naughtiness of thine heart; for thou art come down that thou mightest see the battle.” David's answer was respectful but decided: “What have I now done? Is there not a cause?”
The words of David were repeated to the king, who summoned the youth before him. Saul listened with astonishment to the words of the shepherd, as he said, “Let no man's heart fail because of him; thy servant will go and fight with this Philistine.” Saul strove to turn David from his purpose, but the young man was not to be moved. He replied in a simple, unassuming way, relating his experiences while guarding his father's flocks. And he said, “The Lord that delivered me out of the paw of the lion, and out of the paw of the bear, He will deliver me out of the hand of this Philistine. And Saul said unto David, Go, and the Lord be with thee.”
For forty days the host of Israel had trembled before the haughty challenge of the Philistine giant. Their hearts failed within them as they looked upon his massive form, in height measuring six cubits and a span. Upon his head was a helmet of brass, he was clothed with a coat of mail that weighed five thousand shekels, and he had greaves of brass upon his legs. The coat was made of plates of brass that overlaid one another, like the scales of a fish, and they were so closely joined that no dart or arrow could possibly penetrate the armor. At his back the giant bore a huge javelin, or lance, also of brass. “The staff of his spear was like a weaver's beam; and his spear's head weighed six hundred shekels of iron; and one bearing a shield went before him.”
Morning and evening Goliath had approached the camp of Israel, saying with a loud voice, “Why are ye come out to set your battle in array? am not I a Philistine, and ye servants to Saul? choose you a man for you, and let him come down to me. If he be able to fight with me, and to kill me, then will we be your servants: but if I prevail against him, and kill him, then shall ye be our servants, and serve us. And the Philistine said, I defy the armies of Israel this day; give me a man, that we may fight together.”
Though Saul had given David permission to accept Goliath's challenge, the king had small hope that David would be successful in his courageous undertaking. Command was given to clothe the youth in the king's own armor. The heavy helmet of brass was put upon his head, and the coat of mail was placed upon his body; the monarch's sword was at his side. Thus equipped, he started upon his errand, but erelong began to retrace his steps. The first thought in the minds of the anxious spectators was that David had decided not to risk his life in meeting an antagonist in so unequal an encounter. But this was far from the thought of the brave young man. When he returned to Saul he begged permission to lay aside the heavy armor, saying, “I cannot go with these; for I have not proved them.” He laid off the king's armor, and in its stead took only his staff in his hand, with his shepherd's scrip and a simple sling. Choosing five smooth stones out of the brook, he put them in his bag, and, with his sling in his hand, drew near to the Philistine. The giant strode boldly forward, expecting to meet the mightiest of the warriors of Israel. His armor-bearer walked before him, and he looked as if nothing could withstand him. As he came nearer to David he saw but a stripling, called a boy because of his youth. David's countenance was ruddy with health, and his well-knit form, unprotected by armor, was displayed to advantage; yet between its youthful outline and the massive proportions of the Philistine, there was a marked contrast.
Goliath was filled with amazement and anger. “Am I a dog,” he exclaimed, “that thou comest to me with staves?” Then he poured upon David the most terrible curses by all the gods of his knowledge. He cried in derision, “Come to me, and I will give thy flesh unto the fowls of the air, and to the beasts of the field.”
David did not weaken before the champion of the Philistines. Stepping forward, he said to his antagonist: “Thou comest to me with a sword, and with a spear, and with a shield: but I come to thee in the name of the Lord of hosts, the God of the armies of Israel, whom thou hast defied. This day will the Lord deliver thee into mine hand; and I will smite thee, and take thine head from thee; and I will give the carcasses of the host of the Philistines this day unto the fowls of the air, and to the wild beasts of the earth; that all the earth may know that there is a God in Israel. And all this assembly shall know that the Lord saveth not with sword and spear: for the battle is the Lord's, and He will give you into our hands.”
There was a ring of fearlessness in his tone, a look of triumph and rejoicing upon his fair countenance. This speech, given in a clear, musical voice, rang out on the air, and was distinctly heard by the listening thousands marshaled for war. The anger of Goliath was roused to the very highest heat. In his rage he pushed up the helmet that protected his forehead and rushed forward to wreak vengeance upon his opponent. The son of Jesse was preparing for his foe. “And it came to pass, when the Philistine arose, and came and drew nigh to meet David, that David hasted, and ran toward the army to meet the Philistine. And David put his hand in his bag, and took thence a stone, and slang it, and smote the Philistine in the forehead, that the stone sunk into his forehead; and he fell upon his face to the earth.”
Amazement spread along the lines of the two armies. They had been confident that David would be slain; but when the stone went whizzing through the air, straight to the mark, they saw the mighty warrior tremble, and reach forth his hands, as if he were struck with sudden blindness. The giant reeled, and staggered, and like a smitten oak, fell to the ground. David did not wait an instant. He sprang upon the prostrate form of the Philistine, and with both hands laid hold of Goliath's heavy sword. A moment before, the giant had boasted that with it he would sever the youth's head from his shoulders and give his body to the fowls of the air. Now it was lifted in the air, and then the head of the boaster rolled from his trunk, and a shout of exultation went up from the camp of Israel.
The Philistines were smitten with terror, and the confusion which ensued resulted in a precipitate retreat. The shouts of the triumphant Hebrews echoed along the summits of the mountains, as they rushed after their fleeing enemies; and they “pursued the Philistines, until thou come to the valley, and to the gates of Ekron. And the wounded of the Philistines fell down by the way to Shaaraim, even unto Gath, and unto Ekron. And the children of Israel returned from chasing after the Philistines, and they spoiled their tents. And David took the head of the Philistine, and brought it to Jerusalem; but he put his armor in his tent.”