"is always active when God is at work for the salvation of souls. When the sons of God come to present themselves before the Lord, Satan comes also among them. In every revival he is ready to bring in those who are unsanctified in heart and unbalanced in mind. When these have accepted some points of truth, and gained a place with believers, he works through them to introduce theories that will deceive the unwary. No man is proved to be a true Christian because he is found in company with the children of God, even in the house of worship and around the table of the Lord. Satan is frequently there upon the most solemn occasions in the form of those whom he can use as his agents. GC 395.3"
"Now there was a day when the sons of God came to present themselves before the Lord, and Satan came also among them."
EGW directly references the event in Job 1:6 where Satan appears among the sons of God, applying it to her context.
"But while men slept, his enemy came and sowed tares among the wheat, and went his way."
The idea of Satan sowing tares among the wheat is thematically similar to EGW's statement about Satan introducing deceptive theories through unsanctified individuals. While not a direct quote, the concept of infiltration and corruption is present in both.