According to Sinclair Ferguson, assurance of salvation is like being married. “Once you’re married, you’re married. It’s yours, you can be sure about it. But you can still struggle with the question, ‘Does she still really love me?’” As a wedding ring is a pledge of your spouse’s love towards you, baptism and the Lord’s Supper are tangible gifts reminding us of our salvation. They reassure us of God’s love for us.

Faith brings assurance, but like in marriage, assurance can grow over time. And just as everyone’s marriage is different (and their experience of being loved in marriage), everyone’s individual experience of assurance is different. “Assurance, in a sense, is shaped individually to us.” Your assurance of salvation is for you; not me or anyone else. I need a sense of assurance that Jesus Christ saved me.

It’s possible for us to grow in assurance, just as our love for a spouse grows with time. “There is an absoluteness about the relationship and there is a progress in it; and that progress is a very individually experienced reality.” How do we grow in the assurance of salvation? How does God lead us on from that initial sense of assurance to the full assurance of salvation? The theologian John Murray said,

The germ of assurance is surely implicit in the salvation which the believer comes to possess by faith. It is implicit in the change that has been wrought in his state and condition. However weak may be the faith of a true believer, however severe may be his temptations, however perturbed his heart may be respecting his own condition, he is never, as regards consciousness, in the condition that preceded the exercise of faith. The consciousness of the believer differs by a whole diameter from that of the unbeliever. At the lowest ebb of faith and hope and love, the believer’s consciousness never drops to the level of the unbeliever at its highest pitch of confidence and assurance.

Right from the beginning, the believer’s consciousness of the Father’s love is always on a higher plane than that of the unbeliever. There are a couple of ways that indicate how this works out. First, assurance is ours because we trust in the sufficiency of Jesus Christ to pardon us and to save us. We need to understand here that we are justified by faith. “But the faith by which we are justified contributes nothing to the justification it receives.”

Faith is the gateway by which we come to Christ. It doesn’t contribute to salvation. “For by grace you have been saved through faith” (Ephesians 2:8). “When we don’t get that clear, our assurance is going to dissipate.” As long as we think our faith contributed to our justification, when our faith grows weak, we lose assurance instead of our faith making us stronger in Christ. “Few things could be more important to us than having a right understanding of how our justification is by faith.”

In the justification of God through faith, the Father loves us just as much as the Son. Some Christians seem to believe that Jesus had to die in order to convince the Father to love us. “If we think in that way, it will not be long before we are doubting whether the Father really loves us or not. We are sure of Jesus, but we’re not sure of the Trinity. And because we’re not sure of the Father, we’re not sure of the Holy Spirit.”

We need to learn to understand that justification is an eschatological reality. By this Ferguson means it is the judgment of the last day being manifest in the present. This is where and when our assurance rests. If you suppose justification to be progressive, only to be completed on the last day, you will never grasp the full assurance of salvation. “Rightly understanding the gospel enables us to trust in the absolute sufficiency of Jesus Christ to save us eternally because He has already justified us now.”

Sometimes when people are struggling with the problem of assurance of their salvation, it is best to refrain from talking to them about assurance. “Their problem and confusion is actually about justification.” As we minister and encourage one another, we need to realize problems with assurance are often problems understanding justification by God’s free grace. So, one of the ways we can grow into an assurance of salvation, given to us by God in the gospel, is by deepening the appreciation of “the reality of what has been given to us in our justification.”

There is a second way by which assurance may grow illustrated in the epistle of 1 John. The gospel of John was written evangelistically (John 20:31). But the first epistle of John was written to those who already believe in the Son of God, that we may have an assurance of our salvation (1 John 5:13). Unfortunately, the first epistle of John is sometimes read as if he were speaking about qualifications for being a Christian. But Ferguson said, “He’s not speaking about qualifications for being a Christian.”

When reading the epistle, it’s as if John was pointing out to the believer various character traits that indicate whether or not they were saved. “If this is true, then you can be sure” of your salvation. We can be assured we have been born of God if we have keep His commandments (1 John 5:2). Only Christians want to please the Lord by keeping His commandments. This is a kind of medicine that begins to deal with the uncertainty. Sometimes the uncertainty is in the psyche; the way the person thinks about himself or herself.

Another character trait of assurance is found if we practice righteousness (1 John 2:29). Those who are born of God live righteously. “Whoever practices righteousness is righteous, as he is righteous” (1 John 3:7). “Only those who are aligned with the gospel live lives aligned with the gospel.” And then John said he was writing these things to us “so that you may not sin.” Ferguson thought what John meant by that statement was, there must be evidence of a radical breach with sin in my life.

“It doesn’t mean that I never commit sin, it means that my relationship with sin has been radically transformed.” Sin and its dominion is a thing of the past. If you live as though sin reigned in your life, you actually live as though you aren’t a Christian. “And if I’m living as though I’m not a Christian, it’s not very likely I’m going to be sure that I’m a Christian.” Without evidence that a change has really taken place, how could you believe that a change occurred?

“Everyone Jesus Christ saves He transforms.” We are transformed by grace through faith. And this is not our own doing; it is the gift of God, not a result of works, so that no one may boast (Ephesians 2:8-9). The gateway of faith is the assurance of things hoped for, the conviction of things not seen (Hebrews 11:1).

This article has been based on “Toward Assurance of Salvation,” the eleventh video in Sinclair Ferguson’s teaching series, The Whole Christ, from Ligonier Connect. Here is a link to Ligonier Connect. The video series is itself based upon his book of the same name. You can review summaries of the Marrow Controversy here and here. If the topic interests you, look for more of my ruminations under the link, The Whole Christ.