"bondage of unbelief has chained your soul. You do not glorify God in your life. Our faith sometimes looks to you very questionable. The reason of this is in yourself. In the world, truth and falsehood are so mixed that one is not always clearly discerned from the other. But why has one who professes the truth so little strength? Because he understands not his own ignorance and his own weakness. If he knew this, if he were distrustful of himself, he would feel the importance of divine help to preserve him from the wiles of the enemy. We need to be active, working Christians, unselfish in heart and life, having an eye single to the glory of God. Oh, what wrecks we meet everywhere! what silent lips and fruitless lives! “This,” said the angel, “is because of falling under temptation. Nothing mars the peace of the soul like sinful unbelief.” 4T 213.2"
"Jesus answered them, Verily, verily, I say unto you, Whosoever committeth sin is the servant of sin."
The EGW passage discusses the bondage of unbelief and its consequences, which aligns thematically with John 8:34, where Jesus speaks about being a servant of sin. While not a direct quote, the underlying principle of being enslaved by sin/unbelief is present.
"You should not give up in despair, thinking you must live and die in the bondage of doubt and unbelief. In the Lord we have righteousness and strength. Lean upon Him; and through His power you may quench all the fiery darts of the adversary and come off more than conqueror. You may yet become sanctified through the truth; or you may, if you choose, walk in the darkness of unbelief, lose heaven, and lose all. By walking in the light and working out the will of God, you may overcome your selfish nature. 4T 213.3"
"Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked."
The phrase 'quench all the fiery darts of the adversary' is a direct allusion to Ephesians 6:16.