No man has ever seen heaven. Many things that we do in life show some kind of faith. A person takes aspirin where he has a headache. Because he believes the aspirin will get rid of the headache. When a person plants maize, he believes that it will grow.
Children have faith in their parents.
They believe their parents when their parents tell them something. We have faith in something because we have heard about it. We cannot have faith without hearing. We plant maize to grow for food. Because we have heard that it will.