The sub-comment for this question was: "That way, more people would believe in Him and there would be less people that have to suffer in hell."
The Bible never sets out to prove the existence of God. It simply makes the statement in Genesis 1:1 - "In the beginning, God..." However, Jesus gave us a wonderful parable (short story) to address this great question in Luke 16.
Beginning in Luke 16:19 Jesus tells the story of a rich man who died and went immediately to "hell." (YES, hell exists; contrary to what some are teaching today) (The word translated "hell" is "hades" and is used here to describe the destination of the unsaved dead prior to the great white throne judgment described in Rev. 20:11-15.) While the rich man was in "hell" he pleaded with Abraham to send Lazarus to warn his five brothers about the horrible place, that they might trust God and be spared the torment (16:27-28). Abraham's reply was that they already "have Moses and the Prophets" and "even if someone rises from the dead" his brothers would not listen.
In other words, God has given us everything we need to believe in Him through the creation and His Word (the Bible). Romans 1:20 says, "since the creation of the world his invisible attributes - his eternal power and divine nature - have been clearly seen, because they are understood through what has been made. So people are without excuse." Even if God was to somehow give further proof of His existence the people would still not believe, just as the rich man's brothers would not believe.
Unbelievably, the Bible gives us an example of this happening in the future. The book of Revelation clearly describes a 1000 year period in which Jesus will reign on the throne of David in Jerusalem (Rev. 20:6). At the end of the 1000 year period there be a group of people who will gather to fight against God before being devoured by fire from heaven. It amazes me that even after all the prophecy of the Bible is fulfilled and Jesus has returned, there will still be people who do not believe.
God gave His call to us through the prophet Isaiah:
Isaiah 45:22-24 states, "Turn to me so you can be delivered, all you who live in the earth's remote regions! For I am God, and I have no peer. I solemnly make this oath - what I say is true and reliable: 'Surely every knee will bow to me, every tongue will solemnly affirm; they will say about me, "yes, the Lord is a powerful deliverer."'"
Turn to God today and trust in His Son, Jesus, for forgiveness from your sins.
