"I was shown that God's true people are the salt of the earth and the light of the world. God requires of them continual advancement in the knowledge of the truth, and in the way of holiness. Then will they understand the coming in of Satan, and in the strength of Jesus will resist him. Satan will call to his aid legions of his angels to oppose the advance of even one soul, and, if possible, wrest it from the hand of Christ. 1T 345.1"
"Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men. Ye are the light of the world. A city that is set on an hill cannot be hid."
The EGW passage directly references and applies the 'salt of the earth' and 'light of the world' metaphor from Matthew 5:13-14 to God's people.