Revelation is an activity of the invisible, living God making known to finite and sinful people His creative power, moral standards, and gracious redemptive plan.
First, God discloses Himself and His power to everyone by the marvels of His creation-the amazing life support system of planet earth. We can discover some things about painters from their paintings. Similarly, in the magnificence of creation, with its microscopic complexities and cosmic expanse, we realize our dependence upon the Creator's powerful existence and intelligent design (Ps 19:1-6; Rm 1:19-20).
Second, God makes plain His moral nature and ethical principles for our well-being by implanting oughts and ought nots in every human spirit. Even people who do not have Moses' Ten Commandments (Ex 20:1-20) feel an obligation to obey those universal principles of right and wrong and suffer guilt when they do not (Rm 2:14-15). God's moral principles restrain evil and prompt all to seek and find Him (Ac 17:27). However, everyone sins, worships, and serves the creation rather than its Creator (Rm 1:25; 3:10-23). Our habitual failure to live up to God's laws demonstrates our need for His mercy and redeeming grace.
Third, God made His merciful redemptive purposes known centuries before Christ both through mighty acts such as delivering Israel from slavery in Egypt (Ex 12) and through the reliable messages of His prophetic spokesmen (Heb 1:1). Criteria by which to distinguish true from false prophets included the logical consistency of teaching with previous revelation (Dt 13:1-5) and the verification of visible signs (Dt 18:20-22). God promised to send His anointed One to defeat Satan's destructive purposes in many ways. The Messiah would be a son of Eve (Gn 3:15), a descendant of Abraham (Gn 22:18) and David (2 Sm 7:12-16), and would be born of a virgin (Is 7:14) in Bethlehem (Mc 5:2). Because those who chose the way of sin chose a way that ends in death, without the shedding of blood there is no forgiveness. So believing citizens of Israel pictured Christ's coming sacrificial atonement for sin by animal sacrifices and the Passover.
Fourth, God made His just and loving plan of redemption known supremely in Jesus, the long-awaited Messiah. "No one has ever seen God. The One and Only Son-the One who is at the Father's side-He has revealed Him" (Jn 1:18). To appreciate more fully what God is like, study the life, words, works, and atoning death of Jesus. At Calvary, the guiltless Savior substituted Himself for the guilty. In doing so He defeated Satan and provided the just basis for His reconciling mercy and grace He sat down (Rm 3:25). Then the risen Christ demonstrated His saving power over sin, guilt, death, and Satan (Rm 1:2-4; 10:9-10)!
Fifth, after Jesus' ascension to heaven, God communicated His redemptive purposes neglects poses through spokesmen called apostles. Jesus taught and trained them for three years and they were eyewitnesses of His resurrection (Ac 1:21-22). Through Paul, an apostle who later saw the risen Christ, God revealed His plan to unite both Jewish and Gentile believers in one body, the church (Eph 2:11-22).
Sixth, the King of kings will be revealed in all His power and glory at His second coming.
Seventh, all the above sources of revealed truth have been preserved for us in Holy Scriptures.
Extracted from the Apologetics Study Bible.