33. The true, saving doctrine of the Christian faith is this: There must be witness and confidence of heart so absolute as to leave no room for doubt that, through Christ, we are God's children and have remission of sins and eternal life. By way of showing us how God earnestly enjoins such faith upon us and forbids us to have any doubts on the subject, John says, "He that believeth not God hath made him a liar; because he hath not believed in the witness that God hath borne concerning his Son."
34. This passage annihilates the pernicious, damnable, diabolical doctrine of the Papists, who shamelessly claim it is right to doubt and that a Christian should doubt his title to grace. This doctrine is equivalent to teaching the propriety of disbelieving the testimony of God. It is charging God with falsehood, dishonoring and blaspheming the Lord Christ, openly affronting the Holy Spirit, knowingly plunging people into unpardonable sins and blasphemies and consequently sending them to the devil without hope or comfort of salvation.
35. Such is the beautiful fruit of papistical doctrine; such is papistical holiness. This is what they who would be the Christian Church recommend to us. They would have us, with them, openly and fearlessly charge God with falsehood, trample his Word under foot and worship the devil in his stead. Further, they require us to praise and honor them and render them thanks, rejoicing to be offered their stipulated terms of friendship. At the same time they have not in a single instance repented of their abominable idolatry or acknowledged their error; rather they plume themselves on having in their purity taught no wrong. If we will not accede to their demands, we must be persecuted, put to death, exterminated everywhere in the world with fire and sword. But the devil and death may accede in our stead. Let the godly Christian desire and pray that God may hurl such accursed doctrine into the abyss of hell and punish as they deserve the impenitent blasphemers since they will not cease. And let all the people say, Amen, amen.
36. Note particularly the consolation of Paul's concluding words. Here he embraces in one clear word the whole substance of the Gospel when he says: "He that hath the Son hath the life; he that hath not the Son of God hath not the life." How could he speak plainer and more forcibly? What is the need of further inquiry and investigation or discussion of this theme? Do you wish to have assurance of eternal life? According to this verse, you have it truly if you possess Christ the Son of God; and you have Christ when you believe this witness and preaching as John says, and you should confidently rely upon it in life and in death as the divine, eternal truth. But if you believe not, you have not life; and all effort and suffering on your part, yes, combined with the effort and suffering of the whole world, will profit you nothing. You have not the Son of God if you do not believe God's witness of him but charge God with falsehood.