Sanctify them through thy truth: thy word is truth. John 17:17.
Assimilation is a law of human nature. Satan works with untiring perseverance to use this law, ordained by God to be a power for good, to forward his plans. He seeks to blend together righteous and unrighteous principles in order that through this union sin may lose its offensive appearance. He mixes chaff with the wheat.
The righteous should associate with the wicked only to restore the principles of truth which have been almost obliterated. He who seeks to help and bless others must depend wholly upon the unseen yet all-essential supply of grace and strength. He must cooperate with God if he would be successful in saving the souls ready to perish. He must associate closely with divine agencies, drawing by faith the grace so much needed to resist the elements of unrighteousness.
Christ saw Satan patterning after heaven by the use of human association, thus extending the contagion of evil, and He determined to make His church a resisting element. His people are not to borrow the forms and customs of the world, but are to be instinct with the principles which make the church on earth a symbol of the church in heaven, a channel through which heaven’s rich blessings can flow.
Untold good may be accomplished by the righteous working with and for the wicked; but too often those who ought to lead sinners to God do not draw with Christ... Church members are under a solemn pledge to form characters different in every way from the characters of worldlings. If a change does not take place in them prior to their union with the church, there is danger that, though they have joined the church, they will assimilate with worldlings. Satan triumphs when he sees the leaven of the world working in the church, to the destruction of its purity and holiness.
It is God’s plan that in His church heavenly influences shall be reinforced and stimulated by the cooperation of the members with Him. His people are to increase in strength and efficiency, knowing that the atmosphere which surrounds the souls of righteous believers is the same as the atmosphere in the heaven of purity and light and love. Through Christian fellowship they are to form their characters, assimilating them to the character of Christ. According to their faith will be their Christlike meekness and lowliness. As God’s people seek to fulfill this plan, they are answering the prayer of Christ, “Sanctify them through thy truth: thy word is truth.”—Manuscript 27a, April 19, 1900, “God’s Purpose for His People.”
Reference: E.G. White, "The Upward Look," p. 123
