"Chapter 31—Hope for the Heathen Throughout his ministry Isaiah bore a plain testimony concerning God's purpose for the heathen. Other prophets had made mention of the divine plan, but their language was not always understood. To Isaiah it was given to make very plain to Judah the truth that among the Israel of God were to be numbered many who were not descendants of Abraham after the flesh. This teaching was not in harmony with the theology of his age, yet he fearlessly proclaimed the messages given him of God and brought hope to many a longing heart reaching out after the spiritual blessings promised to the seed of Abraham. PK 367"
"And he said, It is a light thing that thou shouldest be my servant to raise up the tribes of Jacob, and to restore the preserved of Israel: I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth."
Both passages discuss God's purpose for the Gentiles/heathen to receive salvation. Isaiah 49:6 is a key verse in understanding this purpose, and EGW's passage directly relates to this theme.
"The apostle to the Gentiles, in his letter to the believers in Rome, calls attention to this characteristic of Isaiah's teaching. “Isaiah is very bold,” Paul declares, “and saith, I was found of them that sought Me not; I was made manifest unto them that asked not after Me.” Romans 10:20 . PK 367.2"
"But Esaias is very bold, and saith, I was found of them that sought me not; I was made manifest unto them that asked not after me."
Ellen White directly references Romans 10:20 in this passage.
"Often the Israelites seemed unable or unwilling to understand God's purpose for the heathen. Yet it was this very purpose that had made them a separate people and had established them as an independent nation among the nations of the earth. Abraham, their father, to whom the covenant promise was first given, had been called to go forth from his kindred, to the regions beyond, that he might be a light bearer to the heathen. Although the promise to him included a posterity as numerous as the sand by the sea, yet it was for no selfish purpose that he was to become the founder of a great nation in the land of Canaan. God's covenant with him embraced all the nations of earth. “I will bless thee,” Jehovah declared, “and make thy name great; and thou shalt be a blessing: and I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed.” Genesis 12:2, 3 . PK 367.3"
"And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed."
EGW directly quotes Genesis 12:3, making this an explicit allusion.
"And ye shall be unto me a kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel."
The EGW passage directly quotes Genesis 12:2,3 and builds upon the concept of Israel being a blessing to all nations, which is the core idea in both Genesis 12 and Exodus 19:6. The EGW passage explicitly references the Genesis passage.