"The men and women at the head of a mission need close connection with God, in order to keep themselves pure and to know how to manage the youth discreetly, so that the thoughts of all shall be untainted, uncorrupted. Let the lessons given be of an elevated, ennobling character, that the mind may be filled with pure, Christlike thoughts. “Every man that hath this hope in him purifieth himself, even as He is pure.” [ John 3:3 .] As God is pure in His sphere, so man is to be pure in his. And he will be pure if Christ is formed within, the hope of glory; for he will imitate Christ's life and reflect His character. GW 366.1"
"Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God."
Ellen White directly references John 3:3 in this passage.