"The 144,000 were all sealed and perfectly united. On their foreheads was written, God, New Jerusalem, and a glorious star containing Jesus’ new name. At our happy, holy state the wicked were enraged, and would rush violently up to lay hands on us to thrust us into prison, when we would stretch forth the hand in the name of the Lord, and they would fall helpless to the ground. Then it was that the synagogue of Satan knew that God had loved us who could wash one another's feet and salute the brethren with a holy kiss, and they worshiped at our feet. EW 15.1"
"And I heard the number of them which were sealed: and there were sealed an hundred and forty and four thousand of all the tribes of the children of Israel."
The EGW passage directly references the 144,000 and their sealing, which is a key element of Revelation 7:4. This is a clear and direct allusion.
"And I looked, and, lo, a Lamb stood on the mount Sion, and with him an hundred forty and four thousand, having his Father’s name written in their foreheads."
The EGW passage describes the 144,000 with the Father's name on their foreheads, directly alluding to Revelation 14:1.
"Behold, I will make them of the synagogue of Satan, which say they are Jews, and are not, but do lie; behold, I will make them to come and worship before thy feet, and to know that I have loved thee."
The EGW passage mentions the 'synagogue of Satan' worshiping at the feet of the saints, which is a direct allusion to Revelation 3:9.
Soon our eyes were drawn to the east, for a small black cloud had appeared, about half as large as a man's hand, which we all knew was the sign of the Son of man. We all in solemn silence gazed on the cloud as it drew nearer and became lighter, glorious, and still more glorious, till it was a great white cloud. The bottom appeared like fire; a rainbow was over the cloud, while around it were ten thousand angels, singing a most lovely song; and upon it sat the Son of man. His hair was white and curly and lay on His shoulders; and upon His head were many crowns. His feet had the appearance of fire; in His right hand was a sharp sickle; in His left, a silver trumpet. His eyes were as a flame of fire, which searched His children through and through. Then all faces gathered paleness, and those that God had rejected gathered blackness. Then we all cried out, “Who shall be able to stand? Is my robe spotless?” Then the angels ceased to sing, and there was some time of awful silence, when Jesus…
"And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory."
The EGW passage is a clear expansion and interpretation of Matthew 24:30, describing the sign of the Son of Man's coming in detail. The cloud imagery and the appearance of the Son of Man are directly related.