But how can we be assured that we are saved? We generally hold that only the Bible teaches absolutely certain truths. However, your name is not in the Bible, nor is mine. So on what basis can we have what the Westminster Confession calls the "infallible" assurance that our faith is true and that we belong to God?
The Confession lists three realities that our infallible assurance is founded on. These correspond to justification, sanctification, and adoption, respectively - putting these in a little different order from the order in which we studied them.
First, the Westminster Confession speaks of "the divine truth of the promises of salvation." Clearly, God promises eternal life to all who receive Christ (John 1:12; 3:15-18, 36; 5:24; 6:35, 40, 47; etc.). His promises are absolutely infallible. How can we doubt them? To be sure, the promises don't explicitly contain your name or mine. But they contain our names implicitly; that is, they apply to us.
Let me give you a similar example. When the eight commandment says, "Thou shalt not steal," it doesn't mention my name. It doesn't say that John Frame should not steal. Does that mean that I am free to take your wallet? Well, of course not. Because "Thou shalt not steal" means "Everybody should not steal" or "Nobody should steal." That includes John Frame. So, although my name is not in the test explicitly, the text applies to me, which is to say that my name is there implicitly. The same is true with the promises of salvation. God promises salvation to everybody who believes. If you believe, then that promise is yours. God promises to save you. And that promise is infallible, certain. You dare not doubt it.
Justification comes from faith, from trusting God's promises, just as Abraham did when he believed what God said, even when God's promise seemed impossible. If you believe God's promise, you are justified, and you also have a right to assurance. Believing God's promise is the instrument of justification, as I put it in chapter 15, the essence of justifying faith (Rom. 4:3, 20-21; Gal. 3:7-9). And continuing in faith brings assurance (Col. 1:23; Heb. 3:14; 6:12). This does not mean, of course, that anyone who raises his hand at an evangelistic meeting is saved. People sometimes do that hypocritically. Faith is an inward reality. But if it is there, you have a right to be assured. If you can honestly say, "I am trusting Jesus for my salvation, not my own works, not my family, not my church, but Jesus," then you can say without doubt that you are saved. And as we shall indicate in the next chapter, you cannot lose that salvation.
The second basis of assurance the Westminster Confession mentions is "the inward evidence of those graces unto which these promises are made." This ground corresponds to the doctrine of sanctification. When we introspect in this way, we are asking if indeed the Lord is sanctifying us.
Under the first basis of assurance I mentioned God's promises. God's promises include a promise of new life, of regeneration and sanctification. God has promised to make his people holy (1 Peter 1:15-16; 2 Peter 1:4). So, as we observe what God is doing within us, as we observe our own progress in sanctification, we "make [our] calling and election sure," as Peter says (2 Peter 1:10-11).
Now, I know that self-examination can be a discouraging business. When we look at ourselves, we see continuing sin, as well as the effects of grace. So, we wonder how we can ever gain assurance by self-examination. Many say that we should not look at ourselves but that we should look beyond ourselves, outward, at the work of Christ, at his word of promise. That was what we advised under the first ground of assurance, and certainly we should not look inward without looking outward at the same time. But it is important not only to look at God's promises but also to see how God is fulfilling those promises within us. The continuing presence of sin should not discourage us, because God does not promise to make us sinlessly perfect in this life. But he does promise growth in grace, growth in holiness. When we see that, it increases our confidence that God's promises apply to us. And if we don't see that, it is a danger signal. In that case we should seriously ask ourselves if we have understood the promises of God. If we see ourselves dominated by sinful patterns, we should ask whether we have really trusted Christ as Lord and Savior.
The third ground of assurance, corresponding to the doctrine of adoption, is "the testimony of the Spirit to our adoption witnessing with our spirits that we are children of God." This confessional statement comes right out of Romans 8:16-17. This is to say that, in the end, our assurance is supernatural. Note in Romans 8 that it is not only the witness of our own Spirit but something over and above that, a witness of God's Spirit with our spirit that we are the children of God. Our scrutiny of God's promises and our own sanctification, in the end, is fallible. We make mistakes in our judgments. But the Spirit never makes a mistake. So, he persuades us that what we observe in God's Word and in our own lives is really true, really evidence of grace.
In chapters 4 and 12, I spoke of the Spirit's work in illuminating God's Word to us. I called that work existential revelation. His work in giving us assurance is no different from that. He is not whispering in our ears some new truths that are not found in the Bible. Rather, he is helping us to understand the promises of God in the Bible, to believe those promises, and to see that they apply to us.
Note the triadic structure of these three aspects of assurance, corresponding to justification, sanctification, and adoption, and therefore to God's authority, presence, and control. This suggests that these three grounds of assurance are not independent of one another but that they work together, that each requires the others. And that is indeed the way we should look at it. The Spirit's witness enables us to be sure of the promises of God and the fruits of our sanctification. The promises of the Word are the promises of the Spirit, who inspired the Word, and he continues to speak through the Word. Our sanctification helps us better to appreciate and apply the promises of God to ourselves.
Given these powerful resources, how can a Christian ever lack assurance? Yet we sometimes do seem to fluctuate between assurance and doubt. The Reformed confessions look at this problem from two perspectives. The Heidelberg Catechism (21) says that assurance is of the essence of faith: you can't really have faith without having assurance. And that is true in a way. If you believe Jesus, as I said earlier, you cannot doubt that his promises are true. And if you believe in him, you cannot doubt that those promises apply to you, because they apply to everyone who believes.
The Westminster Confession differs somewhat from the Heidelberg Catechism. It says, "This infallible assurance doth not so belong to the essence of faith, but that a true believer may wait long, and conflict with many difficulties before he be partaker of it" (18:3). The Confession adds:
True believers may have the assurance of their salvation divers ways shaken, diminished, and intermitted; as, by negligence in preserving of it, by falling into some special sin which woundeth the conscience and grieveth the Spirit; by some sudden or vehement temptation, by God's withdrawing the light of his countenance, and suffering even such as fear him to walk in darkness and to have no light: yet are they never utterly destitute of that seed of God, and life of faith, that love of Christ and the brethren, that sincerity of heart, and conscience of duty, out of which, by the operation of the Spirit, this assurance may, in due time, be revived; and by the which, in the meantime, they are supported from utter despair. (18.4)Note the difference from the Heidelberg: the Westminster statement says that assurance does not so belong to the essence of faith as to preclude periods of doubt. The bigger picture is that if we believe in Christ, we have assurance in our heart; but that assurance can be weakened by sin of various kinds, so that our psychological feeling of assurance has its ups and downs. Assurance is logically implied in faith, but sin sometimes weakens our confidence that our faith is genuine. But God has given us adequate resources to return to a state of full assurance. He has given us his promises, his sanctifying work, and the Spirit's testimony. We have a right to assurance if we believe God's promises. When we are in doubt, we should keep coming back to those resources and to the means of grace, which we shall discuss in chapter 20: the Word, worship, prayer, and Christian fellowship.