"Chapter 1—True and False Theories Contrasted The sanctification set forth in the Sacred Scriptures has to do with the entire being—spirit, soul, and body. Here is the true idea of entire consecration. Paul prays that the church at Thessalonica may enjoy this great blessing. “The very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ” ( 1 Thessalonians 5:23 ). SL 7"
"And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ."
EGW directly quotes 1 Thessalonians 5:23 to support her point about sanctification.