What Is Christian Assurance?

Sunday’s sermon will be from Psalm 56. It’s similar to the other “Psalms of David” in this section: David is in a dilemma, but he trusts God anyway. And so David’s faith becomes a model for us. He’s meant to be a try-this-at-home example of weathered, resilient, genuine faith. 

But when we read the refrain in Psalm 56 (see verses 3–4 and 9–11) we might notice a different volume than we’ve seen in the previous psalms. It’s especially “turned up” in verses 9b-11:

“This I know, that God is for me. 
  In God, whose word I praise, 
in Yahweh, whose word I praise, 
  in God I trust; I shall not be afraid. 
What can man do to me?”

This is faith, of course, but it’s a deep, robust kind of faith. It’s a strong, stubborn, anthem-heralding kind of faith. It’s the kind of faith that has been historically called the “assurance of faith” or the “assurance of salvation.” We see the evidence of assurance throughout Scripture, especially at several places in the New Testament, and I think it’s vital for joy (and peace and comfort) in the Christian life. 

So I’m going to spend quite a bit of time talking about assurance in this sermon, and in that way it’ll be unusual. Rather than do a verse-by-verse exposition, I’m planning to explain Psalm 56 in a nutshell and then focus in on assurance, including what it is and what it’s not. 

Of course I can’t say everything, but I’m aiming for at least a primer on the topic, and there are a couple things I’d like to mention now, in view of Sunday.

First, assurance and security are different

For a shorthand definition of assurance, I refer to the Puritan Thomas Brooks who explains assurance as “not having grace, but knowing that you have grace.” It’s not to be saved, it’s to know that you are saved. 

So please get this: assurance is not a reality of salvation, it’s our experience of salvation. This is why “assurance of salvation” and “security of salvation” are different. When you hear about the security of salvation, that’s another way to speak of the perseverance of the saints. It’s a teaching taken from verses like 1 Corinthians 1:8 —

“… as you wait for the revealing of our Lord Jesus Christ, who will sustain you to the end, guiltless in the day of our Lord Jesus Christ.”

Or 1 Peter 1:4–5 —

“He has caused us to be born again to a living hope … to an inheritance that is imperishable, undefiled, and unfading, kept in heaven for you, who by God’s power are being guarded through faith for a salvation.”

See, security refers to the reliability of our final salvation, which is entirely in God’s hands, not ours. It’s God’s promise to us about salvation, and it’s part of salvation from the start. It comes in the package. Every Christian has this security. Assurance is different because it’s about our experience of salvation — such as how robustly we believe and enjoy the comforts of our security.

So, second, assurance does not save you. 

We are justified by grace alone through faith alone in Christ alone. We examined this in Galatians, and there’s no confusion. Only Jesus saves, and he saves all the way. 

I want to make this is super clear because the topic of assurance has been misunderstood and misused. Growing up, I heard it said by pastors and camp speakers that “to be 99% sure you are saved is to be 100% lost.” This is to distort assurance and elevate it in a way that is heresy. It’s categorically untrue, and nowhere supported in Scripture. It is a false teaching that pushed me to a crisis at one point in my life. The real words of Scripture brought me out.

We are saved not by the quality of our faith, but by the object of our faith — Jesus Christ.

Assurance — which is a deeper, robust kind of faith — doesn’t change anything about the reality of our salvation, it only describes our experience of it. And I pray, as Paul does in places like Ephesians 3:16–19, that we do experience more deeply this reality, and that we’d apply more fully its wonder, but that we never confuse our experience and application to be what saves us. It’s only Jesus, and Jesus all the way.

I’m looking forward to examining this topic more on Sunday.