How do I know God exists?

How do we know God exists? Most of the arguments for God's existence center around creation.

Romans 1:19-20 "because that which is known about God is evident within them [unbelievers]; for God made it evident to them. For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they were without excuse." NASB

Here we see Paul explaining that even unbelievers know that God is there, because the since we were created God made Himself known to us. We are without excuse to accept His existence.

There are four basic logical arguments for God's existence that also center around creation. The first, known as the cosmological argument looks at the way the universe works and notices that everything has a cause. This is almost like Newton's laws in science, ever action has an equal and opposite reaction. Looking at this statement the other way, if some object is moving, there had to be an action, or cause, to put that object in motion. The world and creation is the same way. There had to be a cause that started the universe. Scientists claim that the big bang was the beginning of the universe, and it may well have been, but by God's design. Even scientists and astrophysicists don't know where the original energy and matter came from. It had to have a cause. Since everything needs a cause, or beginning, we must follow it back to something that has no beginning and no cause in and of itself. This being is God.

The second argument is called the teleological argument. It sees that life and creation has order, purpose and function. Someone had to design the world to work the way it does. Someone had to design our bodies to work exactly like they do. If the universe were to expand at a faster or slower rate than it is, we would not be alive. That's design! Since creation clearly has some intelligent design and function, there must be a Designer, which is God.

The third argument is called the ontological argument. Think of a being that is greater than anything you can imagine. Now, for that being to be truly greater than anything you can imagine, it must actually have the quality of existing. If it didn't exist, it wouldn't be greater than anything you can imagine.

The fourth argument is called the moral argument. Since man has an innate sense of right and wrong (i.e. we know it's wrong to murder someone and it's OK to breathe), there must be someone who put that moral law on our hearts. In other words, our moral standard is God. We can judge what is right and wrong by what God deems right and wrong.