These questions are often asked in battle of ideas. I believe that these and other questions of the existence of the God of the Bible can be answered with well-reasoned intelligence. We can know that God exists is because He has said as much, and has revealed Himself to us. If God were silent, there would be no value to us for Him to exist, but fortunately for us this is not the case. Not only has God communicated to us the fact that He exists, but He has also told us all about who He is, what He is like and what His plans are for us.
Revelation Through Creation
The first way that God has revealed Himself is through His revelation. Some might say that this position commits the logical fallacy of begging the question, or assuming the point which you are trying to prove. But this is not the case, as we will see.
As the Jewish King David stated that:
The heavens declare the glory of God;
And the firmament shows His handiwork.
Day unto day utters speech,
And night unto night reveals knowledge.
There is no speech nor language
Where their voice is not heard.
There line has gone out through all the earth,
And their words to the end of the world. (Psalm 19:1-4, NKJV)
In other words, nature — specifically, the sky above — testifies of the existence of a Creator. Ancient civilizations confirm this notion. In every part of the world, archaeology has shown that ancient cultures believed that there was some kind of deity connected to the sun, moon and stars. Through their observation of the heavens, they concluded that there must be something beyond themselves.
The Apostle Paul echoed David’s sentiment:
The wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, because what may be known of God is manifest in them, for God has shown it to them. For since the creation of the world His invisible attributes are clearly seen, being understood by the things that are made, even His eternal power and Godhead, so that they are without excuse (Romans 1:18-21).
But the problem with all of those ancient civilizations is that they arrived at the wrong conclusion. Paul continues and explains this error:
[B]ecause, although they knew god, they did not glorify Him as God, nor were thankful, but became futile in their thoughts, and their foolish hearts were darkened. Professing to be wise, they became fools, and changed the glory of the incorruptible God into an image made like corruptible man — and birds and four-footed animals and creeping things (Romans 1:21-23, NKJV).
All of the deities these ancient civilizations were worshiping resembled something within the natural realm. Their gods were modeled after things they were familiar with. Their gods were created in their image, as opposed to them being created in the image of their God. Of all the ancient civilizations only the Hebrews were able to discover who the Creator really was.
Revelation Through Scripture
According to Hebrews 11:6, this fundamental understanding of the existence of God is primary for us as we approach God. Secondarily, we must diligently seek Him and believe that He will reward our search. This is where we go beyond a universal revelation of God, to a special revelation of God. The Jews were rewarded because of their diligent search for God, specifically the search of the patriarch Abraham when he left his home and followed after the voice of God. As a result, to Abraham’s decedents — the Jewish people — “were committed the oracles of God” (Romans 3:2). Their faith in God’s existence through general revelation led to God rewarding them with special revelation.
We refer to this special revelation as the Bible. The Hebrew Scriptures were God’s way of revealing Himself to mankind. The Bible is more that a mere book; it is the Word of God. The evidence for this claim is quite convincing if we approach it with an open mind.
The Bible itself makes numerous claims that could be considered outrageous if it were not the Word of God. As a result of those claims, many have tried to destroy this book. Martin Luther stated:
Infinite potentates have raged against this book, and sought to destroy and uproot it — king Alexander the Great, the princes of Egypt and of Babylon, the monarchs of Persia, of Greece, and of Rome, the emperors Julius and Augustus — but they nothing prevailed; they are all gone and vanished, while the book remains, and will remain for ever and ever, perfect and entire, as it was declared at first. Who has thus helped it – who has thus protected it against such mighty forces? No one, surely, but God himself, who is the master of all things.
The French philosopher and skeptic, Rousseau, saw the uniqueness of the Bible:
I must confess to you that the majesty of the Scriptures astonishes me; the holiness of the evangelists speaks to my heart and has such striking characters of truth, and is, moreover, so perfectly inimitable, that if it had been the invention of men, the inventors would be greater than the greatest heroes.
Approximately 2500 prophecies appear in the pages of the Bible, about 2000 of which already have been fulfilled to the letter—no errors. (The remaining 500 or so reach into the future and may be seen unfolding as days go by.) Since the probability for any one of these prophecies having been fulfilled by chance averages less than one in ten (figured very conservatively) and since the prophecies are for the most part independent of one another, the odds for all these prophecies having been fulfilled by chance without error is less than one in 102000!
Revelation Through Incarnation
Another way God has revealed Himself is by appearing to us in human flesh. Jesus was the almighty God that became a man. The Apostle John testified of this fact. In the introduction to his account of the life of Jesus John references the opening of Genesis and the creation account. “In the beginning was the Word, and the Word was with God, and the Word was God” (John 1:1). Then, a few verses later, John explains that “…the Word became flesh and dwelt among us, and we behel his glory, the glory as of the only begotten of the Father…” (John 1:14). And John makes it unmistakably clear that the purpose of Jesus coming to earth was to “declare” and reveal who God is and what He is all about (John 1:18).
If anyone ever had a question about what God is like, they would only need to look at Jesus. As Lord Byron said, “If ever man was God or God was man, Jesus Christ was both.”
Through fulfillments of prophecies in His birth, life and death, His miracles, His resurrection, and His ascension, Jesus proved that He was God in ways that no other person or supposed deity ever has or ever will. There is no need to look for another God, because Jesus has established His superiority as the King of kings and the Lord of lords.
Through this trifecta of truth: the observable creation, the Biblical revelation, and demonstrable incarnation, we have three very strong reasons for the existence of God. A case that no other religious or philosophical system is able to provide, thus there is no reason to look any further.