There are two chief ways by which God has revealed Himself to men; the light of nature, and the book of scripture. Light of nature, which we call natural or general revelation, refers to the general truths that can be known about God through nature. Special revelation refers to the more specific truths that can be known about God through the supernatural. Scripture is the written form of God’s special revelation that communicates the Gospel of Jesus Christ.
Light of nature denotes three things: (1) the creation (cosmos), (2) natural law, and (3) human faculty of reason. We are made in the image of God, and even though we are fallen creatures, God’s image remains stamped upon us. There is a connection between the natural knowledge men have as God’s image-bearers and the world God has created. The world that we see and the world about which we read tell us of our Creator and Provider.
God may be discovered by the light of nature, we mean that the senses and the reasoning powers, which belong to the nature of man, are able to give him so much light as to manifest that there is a God. – Robert Shaw, Exposition of The Westminster Confession of Faith
The whole creation testifies about its creator. Psalmist declares, “The heavens declare the glory of God; the skies proclaim the work of his hands” (Ps. 19:1). It is impossible to live on this planet without recognizing God, as nature is proof of His existence. By observing how specific and exact the interworkings of creation are, one can only conclude that there is a God. Light of nature renders people inexcusable before the divine bar, as Paul states in Romans 1:19-21.
For what can be known about God is plain to them because God has shown it to them. Ever since the creation of the world his invisible nature, namely, his eternal power and deity, has been clearly perceived in the things that have been made. So they are without excuse; for although they knew God they did not honor him as God or give thanks to him, but they became futile in their thinking and their senseless minds were darkened. – Romans 1:19-21
In this text, Paul gives five facts about the natural revelation. First, it is clear and unambiguous. It is plain and has been clearly discerned. Second, this knowledge “gets through” to the man. God did not merely make available some revelation of Himself that may or may not be discovered and understood by men. They knew God. The problem is that man refuses to acknowledge what he knows to be true. Third, this revelation is not a once-for-all event. It has been going on since the beginning of the world. Fourth, the whole creation is a glorious theater that gives a magnificent display of its creator. Fifth, this revelation is sufficient to render man inexcusable. No one will ever be able to say to God, “I didn’t know you existed. I didn’t think there was sufficient evidence to affirm your existence.”
The belief in the existence of God and general knowledge of the difference between good and evil are ingrafted in all men’s hearts. The man by virtue retains some notions about God, and the difference between what is moral and immoral, and demonstrates an eagerness for good behavior. Natural law is a common set of principles put into the hearts and minds of human beings by God himself, warning them what they should do and what they should avoid. Natural law has three functions: (1) to teach the difference between good and evil, (2) to obligate human beings to good and protect them from evil, and (3) to condemn and convict people when they violate its principles.
When Gentiles, who do not have the Law [since it was given only to Jews], do instinctively the things the Law requires [guided only by their conscience], they are a law to themselves, though they do not have the Law. They show that the essential requirements of the Law are written in their hearts; and their conscience [their sense of right and wrong, their moral choices] bearing witness and their thoughts alternately accusing or perhaps defending them. – Romans 2:14-15
God has written His laws upon the conscience, which either brings fear or comfort to people because they either heed or disregard the testimony of conscience. By nature, people judge and perform external acts using that natural light of conscience. These things do not require proof because they are self-evident.
Human Faculty of Reason
Man is made in the image of God, and he is a rational being. However, the fallen man’s reasoning power is corrupted by sin. There are certain things known by reason, and man still has a residue of reasoning power to obtain a knowledge of that in which he is to believe. People continue to use reason to access and interpret the world around them. They can know there is a God through the observation of the creation using the reasoning ability available to them: by way of causality, elimination and prominence.
Every human has access to the facts and they are universally available to all. When unbelievers are presented the gospel in conjunction with rational arguments and evidence, they can intellectually receive and comprehend the message. But, that does not mean that they will accept and trust those arguments.
Light of nature leaves men inexcusable but not sufficient to save
The light of nature shouts out that God exists and proclaims his power and might, that he created the world, and that he made human beings in his image and inscribed his law upon their hearts. By the light of nature, people are taught sufficiently that there is a just God who is a punisher of wickedness, and that he is the governor of this world, and that he is the author and giver of life. Even though the light of nature manifests the goodness, wisdom, and power of God, as to leave men inexcusable, they are not sufficient to give that knowledge of God, which is necessary for salvation. Yet, it should lead humans to seek to discover who this Creator is.
Fallen human beings are incapable of believing God in a saving manner by the power of unaided reasoning. No amount of rational argumentation, evidence, or sweet-talking will persuade the unbeliever to turn to God in repentance. Only a sovereign work of the Holy Spirit can remove the detrimental effects of sin and enable fallen people to believe in the true God and submit to his commands. God is faithful to bring His special revelation (gospel truth) to all who seek Him through the natural light they have been given. When reason is sanctified by the Spirit, it becomes a useful tool for the rational comprehension of the spiritual truths in the book of Scripture.
None of us was an eyewitness of the action of God in creation. Yet we trust that the universe has come into being by the act of God’s divine work of creation because we have come on reasonable grounds to believe that God’s Word is trustworthy. Because we are convinced that God’s Word is trustworthy and that it is a reasonable conviction, we can trust God’s Word even for those things that we cannot see.