What Is the Difference Between Believing and Knowing?

Questions about the difference between believing and knowing from a biblical perspective, why it’s considered bad manners to ask for testable, repeatable evidence for the existence of gods, and why Christians don’t prove God exists by asking him to change carbon dioxide into hydrogen.   How would you understand the difference between believing and knowing from a biblically informed Christian perspective, with knowing from a secular perspective being that which one can see, smell, touch, or demonstrate empirically? Why is it considered very bad manners to ask for testable, repeatable, consistent evidence that gods and goddesses do exist? What prayer can anyone say over a small amount of baking soda so that when vinegar is poured onto it, the bubbles test positive for hydrogen instead of carbon dioxide, thereby giving evidence that the supernatural being to whom the prayer is offered does exist?