The promises of God we often turn to are those that offer help with our daily life and its battles. But the promise we look at here is a promise that God will make us holy—that is, like himself.
This must be the best of all promises. It’s our one chance to be what we really are. We are God’s image, and if we are not reflecting him, every part of us is working hard to be something we are not built for.
This promise that God will make us holy—or sanctify us, is absolutely necessary. It’s like a parent’s confidence that their baby can walk. God believes we can be holy—and will make it happen. That’s what we need to hear.
Like Paul, we can ask God to sanctify young Christians, and keep them so they will be entirely blameless for when Christ returns. And Paul adds, ‘God is faithful. And he will do it’ (1 Thessalonians 5:23-24). To another group, he says God will keep them guiltless—to the very end. And he adds, ‘God is faithful’ (1 Corinthians 1:7-9). This is very different from telling people they are on their own!
If we are going to be godly—that is, trust him and become like him, we will need to know that this is something God has promised to do.
This is illustrated dramatically when Peter promises Jesus that he will be a faithful disciple. The Lord contradicts him. And by morning, Peter knows that his claims have been empty (Luke 22:31-34). But Jesus has prayed for him that his faith will not fail. And this is exactly what happens. He fails, but not his faith.
He thought he loved Jesus. Jesus knows better (John 14:28). But God’s promises are fulfilled, and, after the resurrection, he knows himself better, and he knows he loves Christ (John 21:15-19). His holiness is dependent on Christ’s prayer and promise.
This is the way with all of us. We fail, even often. But because God makes a promise to keep us, we get up again and make progress.
What Jesus is doing here is fulfilling God’s promise to write his law on our hearts (Jeremiah 31:31-34). In other words, what God commands will become what we want to do. And God vows to relate to us in such a way that this will happen. He will forgive our sins and enable us to know him.
God also promises to fill us with his Spirit. Instead of having hard hearts, he will make them clean and will live in them. And what he wants will be what we want (Ezekiel 36:25-28).
These promises are part of a new covenant that God makes when his earlier covenant has been broken. And it is this covenant that Jesus puts into action. Just before his death, he gives a cup of wine to his followers and says ‘this cup that is poured out for you is the new covenant in my blood’ (Luke 22:20).
This means that if we take the ‘cup’ he offers—if we entrust ourselves wholly to what he does when he dies for us, God will fulfil the promise he made and forgive our sins, enable us to know him, and his law will be written on our hearts. We will pray the Lord’s prayer with enthusiasm— ‘May your will be done on earth as it is in heaven’ (Matthew 6:10).
Don’t underestimate what is going on here. Our situation is hopeless. Jesus must do, for us, what we will not and cannot do for ourselves. We should love the Lord our God with all our heart, soul, mind and strength, and our neighbour as ourselves. But we don’t. And we should suffer God’s judgement for our failure. And we can’t do this without being destroyed forever.
But Jesus is keeping this new covenant promise. Because we share with Christ—in his body and blood—that is, in what he does with his body and blood, we will know God as he really is. We will want to live as his people. And he will forgive all that has happened beforehand.
We need to know this new covenant promise well. Here’s how it is spelt out by the apostles.
First, the letter of Hebrews tells us that we are forgiven—completely (Hebrews 8:6, 10-12; 9:14, 24-26). Sin has effectively been ‘put away’.
The sacrifice Jesus offers to God for our sins turns a light on inside our conscience. We can stop debating with ourselves about what we have done. We can stop inventing ways to appear righteous. Instead, our cleansed conscience can tell us what to run from and what to give ourselves to.
And when Jesus enters into God’s presence on our behalf, we travel there with him (4:14-16). We are ‘at home’ with God and want to please him.
Second, Peter, as we have seen, is renewed by this new covenant promise. He says there are many promises—great and precious. They enable us to share in what God is like (2 Peter 1:3-11).
Peter is not suggesting we be lazy. He urges us to give everything we have to pleasing God. We need to get some virtue into our faith, and some knowledge, self-control, steadfastness, godliness, affection and love. All these take work, but we have the enthusiasm for it because we know God is reliable. He’s guaranteed that our godliness is going to happen.
On the other hand, if we don’t do this, Peter says we have forgotten we are forgiven! God’s forgiveness is not just him emptying our trash can. It’s Jesus showing us that God is totally reliable and gracious. We’ve not just had an experience. We’ve met a person.
Third, Paul tells us how bold this can make us (2 Corinthians 3:4-18). There’s no life in just having instructions. The world is handing out instructions all the time but it has no power to put love in people’s hearts.
The promise we are living under is actually the outshining of God’s glory in Jesus Christ (2 Corinthians 4:6). And while we keep looking at Christ rather than at ourselves, we are being changed—being made more glorious!
With hope like this, we have every reason to be confident. And this is what God wants. We can come to him, we can live in this world, and we can look forward to the future God is making.