Assurance was one of the war-cries of the Protestant Reformation. Because we are justified by faith alone, by Christ alone, then assurance is the birth right of every Christian.
But, we need to be careful about how we understand assurance, within the broader matrix of who God is, and what it means to have faith in him. Otherwise, sadly and ironically, the doctrine or assurance could cause us to fall away.
Our assumption re the nature of assurance is based on our assumptions concerning the nature of the bible, and what it means to trust Jesus – to have “faith”. God is a person, not a thing. Jesus is a person, not a thing. The Holy Spirit is a person, not a thing - nor an impersonal power. We – humans, Christians – are people, not things.
The relationship between things is static, because things are static. You put two rocks down side by side, and measure the distance between them. That’s it. We know for certain the distance between them. And they don’t do anything any more. They just sit there.
The relationship between people is constantly dynamic, because people are alive – dynamic, active. A good, healthy relationship between people is active in a positive way – it is growing, improving. Stasis is bad for relationships – it indicates stagnation, boredom. If married people say they’re bored with each other, pastors and counsellors get worried. And definitely, decline – anger, arguments – is bad for relationships.
God promises that the Holy Spirit will keep us trusting Jesus. But the nature of that continued trust is active, dynamic – it’s a living trust. That’s because it’s between two people: us, and the Triune God (actually, it’s a relationship in the Trinity himself, because it’s trust in the Father, through Christ, in the Spirit… but never mind, we won’t go into that now…).
Because the nature of Christian faith is personal trust in a person – not the impersonal clarity of mathematics, like the distance between two rocks – Christian assurance also has this personal element. We trust the Father to keep us trusting Christ the Son by the power of his Holy Spirit.
The way the Holy Spirit keeps us trusting Jesus is through constantly feeding our faith. And he feeds our faith:
- Positively: by showing how good and attractive Jesus is: his kindness, mercy, truthfulness, justice, power etc;
- Negatively: by showing how bad it would be to not trust Jesus. This includes, among other things:
- Showing how powerless idols are, therefore how stupid idolatry is;
- Showing how weak we humans are, therefore we can’t be arrogant about our own abilities;
- Warning us about the consequences of falling away. These warnings are true, not hypothetical, in the sense that they truly speak of what happens to those who turn away from Jesus. The Spirit uses them to warn believers: don’t go there!
Christians can sometimes think assurance is like mathematical certainty – the distance between two rocks – rather than personal trust in a mighty saviour. They reason it out like this:
1) God promises he won’t let his people fall away;
2) God has made me one of his people – he has brought me to trust Jesus;
3) Therefore, I can’t fall away.
This is logically correct, but unhealthy for Christian discipleship. This is because it implicitly treats assurance, and faith, and God and humans in terms of mathematics rather than people. It’s the wrong kind of faith, in the wrong kind of God.
The practical result of the above logic is: the person who believes that stops listening to the warning passages of the Bible. They bounce off him or her, because they say “that can’t happen to me.” So his doctrine of assurance, instead of encouraging them to listen to the Bible and take it seriously, becomes armour against listening to the Bible. And that is never healthy.
Instead, if we see faith as a living, personal trust in a living person – our faith in the risen, mighty Lord Jesus – then we will rightly see these warnings as his kindness. He is warning us about what really happens if we stop trusting him. And we believe the warning – we take it seriously, we say “yes, that could happen to me if I'm not careful” – and we don’t fall away.
So, can we be sure that true Christians will never fall away? Yes we can. But it’s because of personal nature of faith – we are sure that the personal God will personally keep us personally true to him. And he’ll keep us true to him through the ordinary means of discipleship – read the Bible – and when you do, believe what it says, and obey it, respond to it – pray, go to church, open yourself up to being encouraged and rebuked by other Christians.
Ironically, a desire for mathematical assurance can actually lead to people falling away, because they stop listening to the Bible. They become hard-hearted and presumptuous, stop listening to people telling them they're wrong, stop going to church... and just spiral down to self-destruction.
More deeply: a false doctrine of assurance could lead to a kind of idolatry: having the wrong kind of faith in the wrong kind of god. They think they’re like rocks measuring the distance to another rock.
We need to let the warning passages of the Bible feed our faith in Christ. Otherwise, we’ll end up blunting the sharp edges which God uses to prod us into true faith, true perseverance and true assurance.