3. The heart of the covenant
‘For this is the covenant that I will make with the house of Israel after those days, says the Lord: I will put my laws in their mind and write them on their hearts: and I will be their God, and they shall be my people. None of them shall teach his neighbour, and none his brother, saying, ‘Know the Lord’, for all shall know me, from the least of them to the greatest of them. For I will be merciful to their unrighteousness, and their sins and their lawless deeds I will remember no more’ (Hebrews 8: 10-12).
Under the new covenant, God’s laws are written on the believer’s heart and mind. Here lies the radical nature of this covenant — God’s holy requirements are no longer set before us as external rules, which we struggle to obey, but become our inward motivations. Quite literally, they become part of us.
Practical righteousness
This is why Paul can make his great statement in Romans 6:13-14: ‘do not present your members as instruments of unrighteousness to sin, but present yourselves to God as being alive from the dead, and your members as instruments of righteousness to God. For sin shall not have dominion over you, for you are not under law but under grace’.
Practical righteousness, then, is a fruit of grace not law. It flows from God’s laws written in the heart and mind of the believer by the indwelling Holy Spirit.
Not everyone in Paul’s day would accept this gracious teaching. They ‘scandalously asserted’ that he was encouraging people to ‘sin that grace may abound’, that Paul was ‘antinomian’ — against the law of God.
But Paul answers the objection. ‘What then? Shall we sin because we are not under law but under grace?’ (Romans 6:15). ‘Certainly not!’, he replies. ‘How shall we who died to sin live any longer in it?’ (Romans 6:2).
Inner principle
What we are saying is that because God’s laws are written in our hearts and minds, we obey those laws ‘from the heart’ — according to an inner principle rather than an external rule.
We are not ‘without law towards God, but under law towards Christ’ (1 Corinthians 9:21). The whole ‘law of Christ’ (Galatians 6:2) — not just the Ten Commandments — has been written in our hearts and minds. ‘The “laws of God”’, says John Owen ,commenting on this verse, ‘are here taken largely, for the whole revelation of the mind and will of God’.
Christ’s people have ‘obeyed from the heart that form of doctrine to which [we] were delivered, and having been set free from sin [we have] become slaves of righteousness’ (Romans 6:17-18).
What ‘form of doctrine’ is he talking about? Surely, the doctrine of the gospel, which speaks of the regenerating power of God; the potent and permanent promises of the new covenant; and the presence in the heart both of God’s Spirit and God’s law. It is because of these things that we are able to obey Christ’s teaching from the heart — ‘we have the mind of Christ’.
Obedience is heart work
That is why Timothy is told, ‘take heed to yourself and unto the doctrine [the teaching] … for in doing this you will both save yourself and those who hear you’ (1 Timothy 4:16).
Obedience begins in the heart; it is a heart work. God has wrought upon our heart, and therein lies all the fruitfulness, finality and fullness of our obedience to Christ. This is why God will not disregard his new covenant people as he once disregarded Israel of old.
As this epistle unfolds, the writer comes to a triumphant affirmation. He is going to tell his readers that they can ‘look to Jesus, the author and finisher of their faith’. He is going to say that because ‘the Lord is my helper I will not fear’ (Hebrews 13:6). If God is for us, asks Romans 8:31, who can be against us?
Consider an example. The old covenant commands ‘you shall not covet’, but the new covenant conveys the means and motivation by which we can comply with God’s will. In Hebrews 13:5 he says, ‘Let your conduct be without covetousness, but be content with such things as you have. For he himself has said, “I will never leave you nor forsake you”.’
There is the heart of the new covenant. See how much greater it is! Under the old covenant men failed, weak through the flesh and justly rejected for their disobedience. But under the new, we have the victorious Christ indwelling our hearts by the Holy Spirit, enabling us to walk in God’s ways while we enjoy the richness of his presence — knowing that we are ‘accepted in the beloved’.
They shall be my people
Not only does it say, ‘I will put my laws in their heart’ but it also says, ‘I will be their God and they shall be my people. None of them shall teach his neighbour saying “know the Lord”, for they shall all know me…’.
John writes, ‘You have an anointing of the Holy One’ (1 John 2:20). Everybody in the new covenant knows God. That is how you know that you are a beneficiary of that covenant — you know God through Christ Jesus.
You have believed in the Lord Jesus Christ; you have been called effectually and powerfully; you have apprehended that you were chosen in Christ before the world began. You do not cavil at such statements of Scripture — they are the glory and ground of your hope.
You know that you are blessed of the Father and that there is a ‘kingdom prepared for you from the foundation of the world’ (Matthew 25:34). You do not look for depths of strength within your own weak frame.
Because you know God as your Father, you know that he is your helper — of whom, then, should you be afraid? Men can do nothing to you that affects eternity; nothing that affects the love of God; nothing that prevents God from being good to you; nothing that prevents him from giving you graciously ‘all things richly to enjoy’.
Powerful witnesses
This heart work fulfils another gracious purpose, for in writing his laws upon their hearts and empowering his people’s lives, the Lord is bearing witness in every generation to his saving gospel in a lost world. Believers are epistles — letters of the Spirit — known and read of all men. They are God’s message to dying sinners in our day. This is the glory that excels, the ministry of the Spirit is written on the fleshy tablets of the heart and not on tablets of stone (2 Corinthians 3).
The beneficiaries of the new covenant are therefore truly ‘charismatic’. The Spirit’s work is not that they should speak in unintelligible languages but that they should declare, in plain, intelligible lives, the glory of him who called them out of darkness into his marvellous light.
We are enabled to walk in this world ‘in sincerity of heart, as to Christ; not with eye service, as men-pleasers, but as bond servants of Christ, doing the will of God from the heart’ (Ephesians 6:6).
Mercy to the unrighteous
And all these inestimable benefits are based on Christ’s obedience — to death upon a cross. For it is on the basis of Christ’s atoning sacrifice that God says, ‘I will be merciful to their unrighteousness, and their sins and their lawless deeds I will remember no more’ (8:12).
We are reminded of this fact every time we come to the Lord’s table, for he said, ‘This is the new covenant in my blood’ (1 Corinthians 11:25). All the benefits of that new covenant are ours because he ‘suffered once for sins, the just for the unjust, that he might bring us to God’ (1 Peter 3:18).
Christ’s blood has purged our consciences; Christ’s Spirit is in our hearts; Christ’s law controls our thoughts and our affections; Christ’s people are our family; Christ’s everlasting kingdom is our destination.
That is the glory of the new covenant. All Scripture has become the ground on which we walk — a watered garden to enjoy. We may pluck food from its branches, for it is full of fruitful things for our benefit, our strengthening, our healing and our guidance — that we might be the ‘living epistles’ of Christ in a dying world.
The new covenant brings us the glory, the love and the grace of God, and all this in Christ Jesus. May the Lord bless to us his fulfilled prophecy — for the days have come in which the Lord has made a new covenant in Christ.
