But if ye turn unto me, and keep my commandments, and do them; though there were of you cast out unto the uttermost part of the heaven, yet will I gather them from thence, and will bring them unto the place that I have chosen to set my name there. (Nehemiah 1:8)
It is sometimes assumed – falsely – that being in covenant with God in the Old Testament was on the condition of obedience and in the New Testament the condition is faith. One is law, the other is gospel. Right?
Since the fall of Adam, faith in Christ is what has made the difference between sheep and goats, believers and unbelievers, the elect and the non-elect.
Faith is the result of repentance (Mark 1:15), a repentance which God gives when he regenerates the heart of sinful man (Ezekiel 11:19). Obedience cannot be the condition because God knows that man is incapable of obeying the commands of God without first having a renewed heart (and even then imperfectly). When God makes His covenant of grace, it is with man who has faith in the obedience of another: the obedience of Christ (Romans 5:19).
In our passage in Nehemiah, we see that the people had to turn – repent – and come to God. This was the condition of the covenant. It was their obedience which demonstrated the sincerity of their repentance.
I can do no better than Wilhelmus à Brakel, Dutch Further Reformation theologian, to describe this truth:
” Obedience and faithfulness to this covenant are not demanded as a condition of the covenant, for God can neither make demands upon a sinner by way of a new covenant nor issue promises upon that condition, as was shown earlier. Rather, it is required as a duty, test, and demonstration of their sincerity—both upon entering into, as well as living in the covenant of grace. The promise which, among others, God makes in the covenant of grace is that He will sanctify them. Thus, no one can enter into this covenant unless he has a desire for holiness, and one can neither assure himself nor pretend to be in the covenant of grace unless he is a partaker of holiness. ―Show me thy faith without thy works, and I will show thee my faith by my works‖ (James 2:18). When holiness is required in the covenant of grace, it is not required as a condition, but as a token of sincerity. True and false partakers of the covenant are hereby distinguished from each other, and by this they are identified. Those who do not obey nor keep His covenant, are no partakers of it, and do not belong to God. However, those who do obey and keep His covenant show that they are partakers of the covenant and belong to God. ”
– The Christian’s Reasonable Service