Christianity is not based on speculative philosophy; it is a revealed faith. The basic claim of the Christian faith is that the truth we embrace comes to us from God Himself.
Christianity makes a distinction between general revelation (in creation) and special revelation (in the Bible).
God is the Source of all truth
God is the source of all truth, not only religious truth. We as creatures could not know anything were it not that God has made knowledge possible for us. Even those with perfect vision, if they were placed in a room filled with beautiful objects, could not see any of the beauty, if the room were immersed in darkness. So, when scientists seek to discern truth in their laboratories while belittling us for our claim to trust in revelation for the content of our religious faith, we can simply point out that they could learn nothing from a test tube were it not for the Creator’s revelation and His gift of the ability to learn through a study of nature.
God’s general revelation is called general because it is given to every human being in the entire world. It is given in and through nature and through the human conscience (which is why it is sometimes called “natural revelation”). “The heavens declare the glory of God” (Psalm 19:1). God has given all human beings a sense of right and wrong (Rom. 2:14-15). General revelation does not reveal God’s work as Redeemer, only His work as Creator. One cannot study a sunset and see the heavens declaring God’s plan of salvation; which is precisely why God’s special revelation in the Bible is necessary for salvation.
Generally speaking, according to Romans 1:18-21, the knowledge that human beings gain through general revelation is knowledge of God’s “invisible attributes,” specifically, “His eternal power and Godhead.” This revelation is plain. But it is our nature as sinners to suppress that revelation in unrighteousness.
Unbelievers attempt to excuse their refusal to come to God by claiming that God has failed to provide sufficient proof of His existence, but the Bible is clear that God’s revelation of Himself in nature and in the human conscience provides us with true and clear knowledge of His character. Our sinful suppression of that revelation does not erase the knowledge of God that He has given us through nature and in our hearts. Therefore, everyone needs the gospel, because everyone has been judged guilty – not for rejecting Jesus, of whom many have never heard, but rejecting God the Father, who has revealed Himself plainly to every human being.
Special Revelation is found (ever since the completion of the Canon) only in the Bible.
In OT times, God spoke to people directly on occasion: through dreams, signs, the casting of lots, and theophany, which is a visible manifestation of the invisible God. The best-known theophany is the burning bush; also the pillar of cloud and the pillar of fire.
Prophets and Apostles
The primary way God communicated with the people of Israel was through the prophets. That is why they began their prophecies with the words, “Thus says the Lord.” Their words were set down in writing and became the written Word of God.
In the NT, the counterpart to the prophet was the Apostle. The prophets and the Apostles form the foundation of the church (Eph. 2:20). The chief mark of an Apostle was that he had received a direct call by Christ. The term Apostle refers to one who is sent or commissioned with the authority of the one doing the sending (Matt. 10:40).
Jesus left no manuscript bearing His signature; He was the author of no book. Everything we know about Him is contained in the NT record that has come to us through the work of His apostles.
False prophets were known for teaching what people wanted to hear rather than true revelation from God. The Israelites were to apply three tests to determine who was a true prophet: (1) a divine call, which is why the prophets were zealous to show they had been called directly by God and commissioned for the task; (2) the presence of miracles. Not all prophets performed miracles, but their ministry was authenticated at the outset by an outburst of miracles that began with Moses and continued in the days of Elijah; (3) fulfillment: the things the prophets announced came to pass; (4) the prophet spoke in harmony with God’s Word (Deut. 13:1-3; Isaiah 8:20).
The Incarnate Word
Jesus Christ is the Incarnate Word (John 1:1, 14), the One who embodies the very Word of God (Heb. 1:1-2). Jesus said to His disciples: “he who has seen Me has seen the Father” (John 14:9). The chief of all Apostles, the One whom God chose as His ultimate vehicle of self-disclosure, is Christ Himself. In Christ we meet the fullness of the revelation of the Father, and it is only through Scripture that we meet Christ.
[Adapted from Everyone’s a Theologian by R.C. Sproul]