Can you see the air? A famous saying says "To see is to believe". But in our life, there are things that we cannot see but we believe that exist. Those things that we only feel, like the air or emotions we have. Same with God. No one see Him personally but we all believe that He exist. We can't talk to Him directly but we can talk to Him through prayers. He was around us all day, guiding and protecting us. We know that there is God not because we saw Him but because we believe. Roger Lee said, "You don't have to see to believe. Believe now and you will see later". @Snowver