"I hope you will be strengthened and established in the faith. The work will surely go forward, whether we advance with it or not. It will be victorious, but the question is: Shall we be victorious with it? May God help you both to feel the need of a deep work of grace in your hearts. Remember that Jesus has bought you with the sacrifice of His own life. “Ye are not your own; for ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.” 5T 571.2"
"For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God’s."
The EGW passage directly quotes 1 Corinthians 6:20, making it a clear and explicit allusion.