"It is difficult for those who feel secure in their attainments, and who believe themselves to be rich in spiritual knowledge, to receive the message which declares that they are deceived and in need of every spiritual grace. The unsanctified heart is “deceitful above all things, and desperately wicked.” I was shown that many are flattering themselves that they are good Christians, who have not a ray of light from Jesus. They have not a living experience for themselves in the divine life. They need a deep and thorough work of self-abasement before God before they will feel their true need of earnest, persevering effort to secure the precious graces of the Spirit. 3T 253.1"
"The heart is deceitful above all things, and desperately wicked: who can know it?"
The EGW passage directly quotes Jeremiah 17:9 ('The heart is deceitful above all things, and desperately wicked') to emphasize the deceptive nature of the unsanctified heart. This is a clear and direct allusion.
God leads His people on step by step. The Christian life is a constant battle and a march. There is no rest from the warfare. It is by constant, unceasing effort that we maintain the victory over the temptations of Satan. As a people we are triumphing in the clearness and strength of the truth. We are fully sustained in our positions by an overwhelming amount of plain Scriptural testimony. But we are very much wanting in Bible humility, patience, faith, love, self-denial, watchfulness, and the spirit of sacrifice. We need to cultivate Bible holiness. Sin prevails among the people of God. The plain message of rebuke to the Laodiceans is not received. Many cling to their doubts and their darling sins while they are in so great a deception as to talk and feel that they are in need of nothing. They think the testimony of the Spirit of God in reproof is uncalled for or that it does not mean them. Such are in the greatest need of the grace of God and spiritual discernment that they may disco…
"For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places."
While not a direct quote, the EGW passage speaks of the Christian life as a 'constant battle' and 'warfare,' which aligns with the concept of spiritual warfare against unseen forces described in Ephesians 6:12. The connection is thematic, focusing on the ongoing struggle against spiritual enemies.