Q. 3:How may we know there is a God?
Answer: The light of nature in man and the works of God plainly declare there is a God; but His Word and Spirit only do it fully and effectually for the salvation of sinners.
Scripture: Romans 1:19, 20; 2:14, 15; Psalm 19:1-3; Acts 17:24; 1 Corinthians 2:10; 2 Timothy 3:15, 16
Comment: There are two types of revelation or knowledge: the first is general revelation (or common knowledge) and the second is special revelation (or spiritual/saving knowledge). General revelation refers to that which is common to man—creation and the light of nature in man (i.e. the conscience working with the law of God written on the heart). This law on the heart is essential to the nature of man being made in the image of God (which was created in true righteousness and holiness, Eph. 4:24). Special revelation is not common to all men—the word of God (or the Scriptures). General revelation does not communicate the wisdom and knowledge leading to salvation (i.e. the redeeming work of Jesus Christ), but only leaves man without excuse (Rom. 1:20). Special revelation is necessary for salvation, for it does contain the wisdom and knowledge leading to salvation (2 Tim. 3:15). However, not all who possess this revelation are necessarily saved, for the Holy Spirit must first awaken sinners to the truth and bring them to repentance and faith (1 Cor. 2:10-14; 1 Thess. 1:4-5). The only way we may know God savingly is by His sovereign grace effectually applied by the Spirit through the gospel (2 Thess. 2:13-14).
 “This was an eternal law and an invariable rule of righteousness by which those things that are agreeable to the holiness and rectitude of the divine nature were required and whatever is contrary to it was prohibited. This law was only internal and subjective to Adam, being communicated to him with his reasonable nature and written in his heart, so that he needed no external revelation to perfect his knowledge of it. And therefore in the history of his creation there is no other account given of it but what is comprised in this (and which is twice repeated) that he was made in the image of God. The apostle teaches us this consists in righteousness and true holiness (Ephesians 4:24). The sum of this law was afterward given in ten words on Mount Sinai and yet more briefly by Christ who reduced it to two great commands respecting our duty both to God and our neighbor (Matthew 22:37-40). And this as a law and rule of righteousness is in its own nature immutable and invariable, as is the nature and will of God himself whose holiness is stamped on it and represented by it.” Coxe, Nehemiah. Covenant Theology: From Adam to Christ (CA: Reformed Baptist Academic Press), 43.