"I was shown that the precious promises of Isaiah 58:12-14 apply to those who labor for the restoration of the true Sabbath. LS 96.3"
"And they that shall be of thee shall build the old waste places: thou shalt raise up the foundations of many generations; and thou shalt be called, The repairer of the breach, The restorer of paths to dwell in. If thou turn away thy foot from the sabbath, from doing thy pleasure on my holy day; and call the sabbath a delight, the holy of the Lord, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking thine own words: Then shalt thou delight thyself in the Lord; and I will cause thee to ride upon the high places of the earth, and feed thee with the heritage of Jacob thy father: for the mouth of the Lord hath spoken it."
Ellen White directly references Isaiah 58:12-14 in this passage.
"I was shown that the third angel proclaiming the commandments of God and the faith of Jesus, represents the people who receive this message, and raise the voice of warning to the world to keep the commandments of God and His law as the apple of the eye; and that in response to this warning, many would embrace the Sabbath of the Lord. LS 96.4"
"Here is the patience of the saints: here are they that keep the commandments of God, and the faith of Jesus."
The EGW passage directly connects the third angel's message with keeping the commandments of God and the faith of Jesus, mirroring the core theme of Revelation 14:12. The connection is strong and intentional.
"He found him in a desert land, and in the waste howling wilderness; he led him about, he instructed him, he kept him as the apple of his eye."
EGW uses the phrase 'apple of the eye' in connection with keeping God's law. Deuteronomy 32:10 uses the same phrase to describe God's care for Israel. While not a direct quote, the thematic parallel is clear and meaningful.