"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. PP 645.1"
"And David rose up early in the morning, and left the sheep with a keeper, and took, and went, as Jesse had commanded him; and he came to the trench, as the host was going forth to the fight, and shouted for the battle."
EGW directly quotes 1 Samuel 17:20, making this an explicit allusion rather than a thematic parallel. The context is also the same.
"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?” PP 645.2"
"And David spake to the men that stood by him, saying, What shall be done to the man that killeth this Philistine, and taketh away the reproach from Israel? for who is this uncircumcised Philistine, that he should defy the armies of the living God?"
EGW directly quotes 1 Samuel 17:26, making this an explicit allusion rather than a thematic parallel. The context is also the same.
"When Saul and all Israel heard those words of the Philistine, they were dismayed, and greatly afraid."
The EGW passage describes the fear of the Israelite army, which is also described in 1 Samuel 17:11. It also quotes David's question, which is very similar to 1 Samuel 17:26.
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 th…
"And Eliab his eldest brother heard when he spake unto the men; and Eliab’s anger was kindled against David, and he said, 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."
The EGW passage directly quotes and elaborates on the biblical text from 1 Samuel 17:28, making it a clear explicit allusion.