It is sometimes suggested that the difference between the Old and New Covenants is to do with conditionality. The old, it is assumed, is conditional, centring on ‘do this and live’. The new, it is said, it unconditional, focusing on the finished work of Christ.

The problem with this conception is that the Old Covenant clearly had unconditional elements built into it. The Abrahamic and Davidic Covenants, for example, are evidently unconditional and clearly point towards Christ. The New Covenant, by contrast, clearly has conditional elements to it. There is a requirement of faith without which one cannot be saved and there is a requirement of works. Both the Old and the New contained conditional and unconditional elements.

Perhaps what is clearer is seeing how the various covenants unfold in the Old Testament to progressively reveal the New Covenant. What is more, we can recognise the unconditional nature of the Abrahamic and Davidic covenants – centring as they do on Christ who is the fullness – as well as recognising the evidently conditional nature of faith and works present in the New Covenant. The question is how we hold all this together?

Just as the Abraham and Davidic Covenants rest on God and his will to work, so the New Covenant rests on God and his will to work. These covenants are, in fact, unconditional because they rest in God himself. At the same time, we can acknowledge the conditional requirements of the covenant on us requiring as they do both faith and to some degree works. We then must say that these covenants will be fulfilled because they rest on God and his will to work, which must include the fulfilment of the conditional requirements in his people.

This means the condition of faith is, indeed, a requirement of the covenants. However, the condition of faith is a requirement fulfilled in us by God himself. That is, faith – as the bible consistently tells us – is a gift from God. It is not something we well up within ourselves but is a gift received from God who fulfils that condition of the covenant in us. Similarly, the condition of works is a requirement fulfilled in us by God himself. The good works that God has prepared for us to walk in, the commands of Christ by which our love for him is evident and which are required for salvation, are fulfilled in us by the Holy Spirit. We do not well up within ourselves the desire or ability to do these good works, but they are worked in us in and through the Spirit of God.

In this way, God puts conditional requirements on his covenant but the covenant itself remains unconditional because God commits to fulfilling the conditions in his people himself. The requirements of the covenant are demanded of us but nevertheless fulfilled in us by God who wills and works these things in his people. The covenant is both conditional and unconditional; it comes with requirements but those requirements rest on God himself who fulfils them in his people so that he remains just and justifier and rightly receives all glory.