1st Samuel 17:10 And the Philistine said, I defy the armies of Israel this day; give me a man, that we may fight together. 11 When Saul and all Israel heard those words of the Philistine, they were dismayed, and greatly afraid.
[Patriarchs & Prophets pp 645>646] 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.”
1st Samuel 17:33 And Saul said to David, Thou art not able to go against this Philistine to fight with him: for thou art but a youth, and he a man of war from his youth.
May God add His blessing to the study of His word. "Good night" and God bless!