How do I know there is a God?
Have you ever thought about how many things you know and believe without having seen them? Take gravity for instance. No one has ever seen gravity, but I see evidence of it is all around. As a matter of fact, we depend on it for almost all of our everyday activities. Gravity holds our cars on the road. It keeps us from floating away into space. We would be in serious trouble without it.
Look at God in very much the same way that you look at gravity. You have never seen him, but you see evidence that he must exist in the world. Whether taking in a soft summer sunset or a late night display of the constellations, know that someone took some serious time and effort to get things just right. The Bible puts it this way, "Every house is built by someone, but God is the builder of everything." (Hebrews 3:4)
Have you ever taken time to look closely at the world in which we live? Get up a little earlier than normal tomorrow and let the sunrise speak for itself. You decide which is more impressive, the beauty of the sunrise or the fact that is has risen every day in the history of the world. You will hear an inaudible voice in that sunrise. It is God's voice. (Psalm 19:1-4)
Perhaps you are more impressed with detail. Take time to count the hairs on one of your arms from your wrist to your elbow. As you notice the delicacy with which each hair is connected, consider how hard plastic surgeons work to duplicate a "normal" hair pattern. They never do get it quite right, do they? All of this is part of God's great attention to detail and more evidence that he does exist.
We have never seen God, but, like gravity, we know he is here. He has taken the time to leave evidence of his existence all around the world in which we live. Take time to notice it. You will see that he is very real. If you want more, definite information, take time to get to know him better in the Bible.