Through general revelation we can know some things about God. Using rationality and reason, we understand that there must be a creator and designer of this vastly complex universe. We can also clearly understand that there is an absolute moral law.
We know right from wrong by our own reaction when wrong is done to us, and we intuitively know we should not treat people this way. However, there is a limit to what we can know about God through logic, rational senses and reason.
This is why special revelation is important. While we’re limited with general revelation, we can know everything God has chosen to reveal to us through special revelation.
Through special revelation, we learn of the truths of (1) the tri-unity of God, (2) the virgin birth of Christ, (3) the deity of Christ, (4) the all-sufficiency of Christ’s atoning sacrifice for sin, (5) the physical and miraculous resurrection of Christ, (6) the necessity of salvation by faith alone through God’s grace alone based on the work of Christ alone, (7) the physical bodily return of Christ to earth, (8) the eternal conscious bliss of the saved and (9) the eternal conscious punishment of the unsaved.
The Bible is the only record of special revelation we have. If we remove special revelation all we are left with is general revelation. All we would know is that there is some kind of God who gave us moral law, and we individually have failed to keep it. We would be incapable of knowing this God, reminded constantly of our own failure to please Him, uncertain of our past or our future, living out or days in a wretched state of miserable ignorance, until we cross the void into the unknown.
What a horrible state of existence that would be! I’m grateful that the Creator of the universe chose to reveal Himself through His special revelation!