In Chapter 17, we established the objective fact of the Perseverance of the Saints: if you are in Christ, you are safe forever. But there is a massive difference between being safe and feeling safe. A passenger on a sturdy ship may be perfectly secure, yet terrified that the ship is sinking.
This brings us to Chapter 18 and the doctrine of Assurance. This is one of the most pastoral chapters in the Confession. It addresses the tender conscience that asks, “I know Christ saves sinners, but how do I know He has saved me?” The Westminster divines provide a nuanced answer that guards against both arrogant presumption and unnecessary despair.
The Confession teaches that while hypocrites may deceive themselves with false hopes, true believers may attain an infallible assurance of their salvation; that this assurance rests on God’s promises, the evidence of grace, and the witness of the Spirit; that it does not belong to the essence of faith (so one may be saved without it); and that it may be shaken by sin or temptation, yet never fully lost.
False Hope vs. True Certainty (WCF 18.1)
The chapter begins with a warning. “Hypocrites and other unregenerate men may vainly deceive themselves with false hopes and carnal presumptions.” Just because someone feels saved doesn’t mean they are. Jesus warned that many will say “Lord, Lord” on the last day, only to be rejected (Matt. 7:22–23). Assurance is not merely a warm feeling; it must be grounded in reality.
However, the existence of counterfeit money does not disprove the existence of real money. “Such as truly believe in the Lord Jesus… may, in this life, be certainly assured that they are in the state of grace.” We do not have to wait until we die to know the verdict. We can “rejoice in the hope of the glory of God,” a hope that will never disappoint us.
The Three Pillars of Assurance (WCF 18.2)
On what is this certainty based? It is not a “bare conjectural and probable persuasion” (a mere guess). It is an “infallible assurance of faith.” The Confession lists three pillars upon which this assurance rests:
- The Divine Truth of the Promises: We look outward to the Word. God has promised that “whoever believes in him should not perish” (John 3:16). If God cannot lie, and I believe, then I am saved. This is the primary objective ground of assurance.
- The Inward Evidence of Graces: We look inward at the fruit. If the Bible says, “We know we have passed out of death into life, because we love the brothers” (1 John 3:14), I can ask myself, “Do I love the brothers?” However, we must be exceptionally careful here. Our works are never the foundation of our assurance—only Christ’s finished work is. Inward graces and outward works serve only as secondary and supplementary evidences, confirming that our faith is alive, never as the primary ground of our hope.
- The Testimony of the Spirit: We look upward to the witness. The “Spirit of adoption witnessing with our spirits that we are the children of God” (Rom. 8:16). This is an experiential work of the Spirit, serving as the “earnest” (down payment) of our inheritance.
Faith Without Assurance? (WCF 18.3)
This is perhaps the most critical distinction in the chapter. The Confession states that “This infallible assurance doth not so belong to the essence of faith, but that a true believer may wait long… before he be partaker of it.”
This careful phrasing teaches us that while assurance is of the essence of faith (for to trust God involves a confidence in His character), it is not so of the essence that the absence of full assurance necessarily means the absence of saving faith. It is the ordinary, healthy experience of the Christian to be assured of their salvation. However, because faith can be weak or assailed, a true believer may “wait long” and conflict with “many difficulties” before enjoying this comfort.
You can be saved without currently feeling the full certainty of it, just as a child is fully part of the family even when they are afraid of the dark. Faith is the hand that grasps Christ; assurance is the conscious enjoyment of that grasp. Therefore, it is our duty to “give all diligence to make his calling and election sure” (2 Peter 1:10), for assurance is the birthright of every believer, intended for their “peace and joy.”
Assurance Shaken and Revived (WCF 18.4)
Finally, the Confession addresses the reality of spiritual depression. “True believers may have the assurance of their salvation divers ways shaken, diminished, and intermitted.”
What causes this loss of assurance?
- Negligence: Laziness in the means of grace.
- Sin: “Falling into some special sin which woundeth the conscience and grieveth the Spirit.” (e.g., David).
- Temptation: “Sudden or vehement temptation.”
- Divine Withdrawal: God “withdrawing the light of His countenance,” allowing us to walk in darkness to test our faith (Isa. 50:10).
Yet, even in the darkest night, the believer is “never utterly destitute.” The “seed of God” remains. The root is alive even when the leaves have withered. By the operation of the Spirit, “this assurance may, in due time, be revived,” and in the meantime, they are “supported from utter despair.”
Conclusion
The doctrine of Assurance is a balm for the anxious soul. It tells us that while our feelings of salvation may fluctuate like the stock market, our possession of salvation is as fixed as the throne of God. We are encouraged to look to Christ’s promises, inspect our lives for fruit, and pray for the Spirit’s witness, knowing that even when we are faithless, He remains faithful.
Key Terms
- Infallible Assurance: A certainty of salvation that is not based on guesswork but on the unchangeable promises of God, though it is not always present in the believer’s experience.
- Essence of Faith: What is strictly necessary to be a Christian (trusting Christ). The Confession teaches that assurance belongs to the nature of faith, but distinctively notes that the reflexive assurance of one’s own state may be absent in a true believer.
- Carnal Presumption: A false assurance held by hypocrites, based on self-deception rather than the work of the Spirit or the promises of the Word.
- Reflex Act of Faith: The act of the mind looking back at its own faith and graces to conclude that one is saved (e.g., “I see that I believe, therefore I know I am saved”), distinguishing it from the direct act of faith (trusting Christ).