We are capable of knowing God's existence by the exercise of our intelligence, by reason. Many arguments suggest themselves which completely convince us of the existence of God.

1. God is the first Cause of all things. Look around you, at the sun above, and in the evenings at the planets and stars. See the earth on which we live, the plants, trees, birds, animals and human beings. Then spend a little time in reflection. Who brought these things into existence? Who maintains them?

2. In the world about us there are many examples of Order. But order of this kind demands an intelligence to produce it. Therefore the world was made by an intelligent Orderer. Think of the eye, that wonderful camera which takes each day thousands of colour photographs developing them immediately; of the ear, that marvellous telephone exchange; of your heart, which pumps the blood to the various parts of your body, even while you sleep.

Reflect on the instinct of the animals, on the growth of a tree from seed to flower. Who is the great artist who has arranged that that seed, which comes from a foreign country, should grow into a tree which is so perfect an imitation of the parent tree? 

3. The voice of conscience and of this we have all had experience. There’s a voice in our head which insists that I must do this, and must not do that.  Conscience speaks of a necessary duty which we owe. It brings us face to face with an obligatory law. That there is a law implies a lawgiver. A command implies a superior who issues the command. That lawgiver, that superior, is God. Conscience is His voice speaking to me. God is the infinitely perfect Being, supremely One. He is a spirit. He is changeless, yet essentially active. God is eternal. To all things that are, God is Present, because He is the source of their being, and yet the universe cannot contain Him.His Power, infinite as are all His perfections, extends immeasurably beyond the limits of the things that He has made.

The starry heavens above,
The clear evidence in Nature of a universal design,
The firm assertion of a moral law within my conscience,
All impel me joyfully to acknowledge the existence of
God my Creator.