Billy Graham: How Do We Know God Exists?

“The heavens declare the glory of God, and the sky above proclaims his handiwork.” —Psalm 19:1, ESV


Have you ever tried to share your faith with someone, but hit a block when they asked, “How do you know God exists?”

Billy Graham received thousands of letters during his ministry filled with all sorts of questions, and he was often asked to prove the God he served.

Here’s one of Graham’s My Answer columns with a practical response to someone having trouble accepting that God is real:

Let me ask you a question: You and I have never met—so how do you know I even exist? The answer is obvious: You know I exist because you’ve seen enough evidence to convince you I exist—perhaps a photograph, or a conversation with someone who has seen me.

And the same is true with God. We believe in Him because He has given us enough evidence to prove to us that He exists. In other words, He hasn’t hidden Himself from us; instead, He has revealed Himself or made Himself known to us. God wants us to know Him—and has done everything He needs to do to make this possible.

How has He done this? One way is through the physical world He created, with all of its beauty and complexity and wonder. Isn’t it more logical to believe God created it than to believe it happened by chance? As the Bible says, “Since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made” (Romans 1:20, NIV).

But God has revealed Himself to us in an even greater way: by coming down to earth and taking on human flesh. That person was Jesus Christ. Do you want to know not only if God exists, but if He loves us? Look at Christ, for He came to demonstrate God’s love for us by His death and resurrection. 

What If They Still Have a Hard Time Believing?

Even Christians sometimes face doubts. How can we have faith in a Saviour we can’t see? Billy Graham provided wisdom on that question as well:

Have you ever asked yourself how many times you act on faith every day? The truth is, we live by faith all the time, and without faith it would be impossible to live. Let me explain.

For example, right now you are probably sitting in a chair as you read this. But did you inspect the chair before you sat down, or did you first send it away to a laboratory to be tested? No, of course not. You believed it would hold you, probably because it’s done so many times before, and you’ve seen it hold other people also. And yet you acted by faith when you sat in the chair. At the same time, it wasn’t unreasonable for you to do so.

Faith in God is something like this. Faith in God isn’t blind or unreasonable, because God has left His “footprints” all around us. … It’s far more reasonable to believe in God than to believe this incredibly intricate universe just happened.


Some say science doesn’t support God’s existence because it can’t be proven through a chemical formula or some other complex equation. Happiness, beauty, and love can’t be proven or measured by a laboratory experiment, either, yet that doesn’t mean they aren’t real.

Read more about God’s existence and share with someone searching for evidence.