The Old Testament narrative is a narrative of both hopelessness and hope. In hopelessness we find that God's people are saved out of bondage and called to be God's peculiar people who display His holiness. As they are called to be God's covenant people, they are given the law for them to keep in covenant with God as they live according to God's holiness. There is a constant trail of the failure of Israel in keeping that covenant and we are reminded that confidence in ourselves to be holy is hopeless. We cannot meet God's perfect standard. The hope in the Old Testament comes as we read of the coming Messiah who will keep God's perfect standard for us and in Him alone God will bring a new covenant forever kept in Jesus. In this new covenant, God's people will only be recognized as those who are in Jesus as our covenant keeper. They will be given a new heart, the indwelling Spirit of God, and they will all - every one of them - know God. Their conscience will be brought to life in a heart that seeks to please our Savior.
Jeremiah 31:33-34 For this is the covenant that I will make with the house of Israel after those days, declares the LORD: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people. 34 And no longer shall each one teach his neighbor and each his brother, saying, 'Know the LORD,' for they shall all know me, from the least of them to the greatest, declares the LORD. For I will forgive their iniquity, and I will remember their sin no more."
Ezekiel 36:26-27 And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. 27 And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
The New Testament consistently testifies to the fact that prior to knowing Jesus, our consciences are seared and dead. In Christ, the Holy Spirit brings regeneration and enlivens our heart and conscience to a life that cares about pleasing God and imitating God's ethical heart. This is something that the Old Testament sacrifices could never do, but in Christ, the indwelling presence of the Spirit in all believers brings the victory of Christ over sin to our consciences.
Hebrews 9:13-14 For if the blood of goats and bulls, and the sprinkling of defiled persons with the ashes of a heifer, sanctify for the purification of the flesh, 14 how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God.
There are so many other verses in Scripture that talk about the way the Holy Spirit guides the believer through our conscience. Paul, in Romans 9:1, speaks the truth in Christ with the Holy Spirit bearing witness in his conscience. In Romans 13:5, Christians should obey the governing bodies (short of sinfulness) for the sake of conscience. In 1 Corinthians 8 and 10 Christians are faced with the dilemma of what to eat and not to eat because our consciences are concerned about the nature of worship. In 2 Corinthians 4:2 Paul appeals to the church to see the purity of his ministry by appealing to their consciences. In 1 Timothy 1, Paul makes an argument for Timothy that his appeal is not just based on holding faith but also in its association with a good conscience. In Hebrews 10:22 we are told that our hearts are sprinkled clean from an evil conscience in the full assurance of faith. In both 1 Timothy 4 and Titus 1 we learn that unbelievers have a seared and defiled conscience. Titus 1:15 To the pure, all things are pure, but to the defiled and unbelieving, nothing is pure; but both their minds and their consciences are defiled.
It is based on these Scriptures and the overall teaching about our conscience in the new covenant, that I am convinced that in Paul's discussion in Romans 2, he can only be speaking about the conscience of believing Gentiles. Regardless of the gentile believers in Rome not having the law as their heritage like the Jewish believers, the gentile believers have the new covenant promise of a heart of flesh, the law written on their hearts, and an enlivened conscience in the Spirit. Romans 2:14-16 For when Gentiles, who do not have the law by nature, do what the law requires, they are a law to themselves even though they do not have the law. 15 They show that the work of the law is written on their hearts (New Covenant believers), while their conscience also bears witness, and their conflicting thoughts accuse or even excuse them 16 on that day when, according to my gospel, God judges the secrets of men by Christ Jesus.
It is the believer, not the unbeliever, that has an enlivened conscience by the Spirit of God. This is the work of the cross. This is the work of God in regeneration. This is the glorious promise of the new covenant in our Lord Jesus who has done what none of us could ever do. This is why new believers change and while mature believers keep maturing. It is why the Bible starts to make sense to us and why we are convicted by and even hate our former sin. It is why we have any interest in holiness at all. It is why we can love each other in the integrity of God.
Because of Christ, we have a Holy Spirit empowered conscience that is continually calibrated to the truth of God's word. It's time for Christians to start believing that in Christ we actually do have everything we need. Thank God for the conscience of a new heart.