If thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised Him from the dead, thou shalt be saved.—Romans 10:9.
I DO not know of any more important truth to bring before an unconverted person than the answer to the question—“What must I do to be saved?”—because that is the beginning of everything with regard to the divine life. A man must know he is saved before there is any peace, or joy, or comfort. The answer is, “Believe on the Lord Jesus Christ, and thou shalt be saved.”
The question that comes right after that from almost every one is, “What is it to believe?” I believe that Jesus Christ is the Son of God; I believe that He came into the world to save sinners. Well, so do the devils. The devils not only believe, but they tremble. I can believe intellectually that Jesus Christ is able and willing to save, and yet be as far from the kingdom of God as any man who never heard about Jesus Christ. To be saved I must believe in my heart, and trust in His atoning work.
 Moody, D. L. (1900). The D. L. Moody Year Book: A Living Daily Message from the Words of D. L. Moody. (E. M. Fitt, Ed.) (p. 21). East Northfield, MA: The Bookstore.