Faith

Hebrews 11:1 Now, faith is being sure of what we hope for and certain of what we do not see.

It is easy to just “say” you have faith in an unseen God who has prepared an unseen Heaven for your unseen Spirit to go to when you die. It is when you serve the unseen God with the tangible things you possess here that Faith becomes real. When in His absence you still give back to Him money you don't have enough of, time you would have spent in other ways and service to Him over self, proclaiming His name to others in the face of ridicule.

By these things you prove to Him and others your faith.