"The angel who unites in the proclamation of the third angel's message is to lighten the whole earth with his glory. A work of world-wide extent and unwonted power is here foretold. The advent movement of 1840-44 was a glorious manifestation of the power of God; the first angel's message was carried to every missionary station in the world, and in some countries there was the greatest religious interest which has been witnessed in any land since the Reformation of the sixteenth century; but these are to be exceeded by the mighty movement under the last warning of the third angel. GC 611.1"
"And after these things I saw another angel come down from heaven, having great power; and the earth was lightened with his glory."
EGW explicitly refers to Revelation 18:1, mentioning the angel who lightens the earth with his glory in connection with the third angel's message. This is a clear and direct allusion to the biblical text.
"The great work of the gospel is not to close with less manifestation of the power of God than marked its opening. The prophecies which were fulfilled in the outpouring of the former rain at the opening of the gospel are again to be fulfilled in the latter rain at its close. Here are “the times of refreshing” to which the apostle Peter looked forward when he said: “Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord; and He shall send Jesus.” Acts 3:19, 20 . GC 611.3"
"And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams:"
The EGW passage connects the outpouring of the Holy Spirit (latter rain) with the prophecies fulfilled at the opening of the gospel (former rain), drawing a parallel to Acts 2:17, which speaks of God pouring out His Spirit in the last days. While EGW quotes Acts 3:19,20 directly, the connection to Acts 2:17 is thematic, linking the outpouring of the Spirit with a powerful manifestation of God's power.