Innate or Inborn Knowledge or Conscience
Inborn knowledge or instinct behaviour, it is the knowledge and behaviour which is not learned. Because what may be known of God is manifest in them, for God has shown it to them. For since the creation of the world His invisible attributes are clearly seen, being understood by the things that are made, even His eternal power and Godhead, so that they are without excuse, because, although they knew God, they did not glorify Him as God, nor were thankful, but became futile in their thoughts, and their foolish hearts were darkened. Paul's conclusion is that the heathen are never without a witness to the presence and personality of God. They have the witness of nature and the witness of their own conscience. However, the heathen have deliberately suppressed these witnesses to the truth and have consistently opted for a lie in place of the truth. They have chosen the course of idolatry, which is always accompanied by debauchery. Thus, God has revealed His wrath from heaven against all ungodliness and unrighteousness of men who suppress the truth of God. In addition, God has given them up to idolatry, to passions of infamy, and to an undiscerning and unapproving mind. Are the heathen lost? Yes, the entire heathen world is lost, deserving condemnation, desiring evil, and desperately wicked.
Romans 1: 21–23. Paul's second line of argument is that the heathen are lost because of the revelation of God to the conscience. They glorified him not as God. As if the natural world around us isn't enough, God has planted in the heart of every man the knowledge that there is a righteous God. Though the heathen knew that He was God and deserved to be glorified, they willfully chose not to glorify Him as God. They did not ascribe to His person the holiness, perfection, and sovereignty which are His alone. Neither were thankful. To add injury to insult, the heathen accepted the good things of nature from the hand of God, but were not thankful for them, But became vain in their imaginations. In order to suppress the witness of the ordered structure of the universe, and the innate testimony of the conscience, fallen man had to develop a reasoning process of imagination. This reasoning is described by God as vain because the whole structure of man-made philosophy is devoid of divine truth and therefore invalid. Thus, by suppressing the truth of God and believing their man-made falsehood, they plunged their foolish heart deeper into darkness.
Condemned by his own judgment. Romans 2:1.
Therefore thou art inexcusable, O man, whosoever thou art that judgest. In the last chapter Paul painted a picture of the deplorable condition of the heathen. The apostle knew, however, that there would be a whole class of men who would say "amen" to what he had said about the heathen. These were the self-righteous moralists. So Paul expands his argument to show that all ungodliness and unrighteousness of men (1:18) includes the moralist as well as the debauched heathen. The moralist is inexcusable when he judges the heathen for sin but is blind to his own sin. He only condemns himself when he condemns another. For thou that judgest doest the same things. It is obvious that the moral man was not involved in the sexual deviations of the heathen, else Paul could not call him a moral man. But he was inwardly living in an identical manner as the heathen was living outwardly. Perhaps the moral man did not commit adultery, but did he lust? Our Lord put them in the same category (Mt 5:27–28). Maybe the moral man did not steal, but did he covet? Stealing and covetousness are listed together in Mark 7:22. Perchance the moral man did not commit murder, but did he hate? The Bible says if you hate your brother you are guilty of murder (I Jn 3:15). No one dares judge another while he is doing the same thing because he is then condemned by his own judgment.
Romans 2:14–16. For when the Gentiles, which have not the law, do by nature the things contained in the law, these … are a law unto themselves. Although the Gentiles do not possess the Old Testament law, nevertheless they do those things which are contained in the law. This is because of the law written in their hearts, their conscience also bearing witness. The Gentiles manifested a moral principle at work in their hearts, because when they broke their own ethical code, their conscience (Gr syneidesis) would prick them and cause them to feel guilt. The result of their guilt, however, was they would excuse themselves by making a defense for their actions. But Jew and Gentile alike must face a day of judgment with God when the secrets of men (Gr ta krypta) are judged by the Lord Jesus Christ according to the truth of the gospel preached by Paul.
Romans 3:9 Paul has shown that the heathen are lost because, even though they had the witness of both nature and conscience, they suppressed God's truth to them. He has shown also that the moral man is lost because even though he outwardly put on a facade to judge the heathen, inwardly he was guilty of the same sins. Likewise the Jew is lost because he has not kept the law, and neither his circumcision, ancestry, nor arguments can save him from the condemnation of disobedience. Now Paul wraps up his argument and the summation assumes the terminology of the courtroom.
2 Thes. 1:7-9 It will be terrible to some; for he will then take vengeance on the wicked. On those that sinned against the principles of natural religion, and rebelled against the light of nature, that knew not God , though the invisible things of him are manifested in the things that are seen. And the truth is, Religion, if it is worth any thing, is worth every thing; and those either have no religion at all, or none that is worth having, or know not how to value it, that cannot find in their hearts to suffer for it. The light of nature, This the Gentiles have, and by this they shall be judged: As many as have sinned without law shall perish without law; that is, the unbelieving Gentiles, who had no other guide but natural conscience, no other motive but common mercies, although Gentiles did not receive the codified Mosaic legislation, they are not oblivious to the essential tenets of the law. The essence of the law is engraved in their hearts. Conscience, though perhaps seared and distorted, contributes its own testimony, while man's intellect either adds its own accusation or else fabricates schemes to evade the combined internal and intuitive witness concerning God's law (cf. 1 Tim. 4:2, note). Consequently entails belonging even to Stone Age aboriginal peoples are guilty of rebellion against God's law.