One can learn about things from the past and from other places. We are conditioned to accept it uncritically, and much of what we hear is little more than hearsay or rumor. The attitude of holding a proposition p to be true where there is some degree of evidence, though not conclusive evidence, for the truth of p. a. Stronger than ungrounded opinion, but weaker than full knowledge. Knowing is considered to entail that p actually is true, while believing p is consistent with the possibility that p is false.
People act in accordance with their beliefs.
It would be inconsistent to worship God while claiming to believe that there is no God. Not all opinions are equal. Mere opinions are completely unsupported b. Reasoned opinions have evidence to support them. There is a popular, but mistaken belief that faith is always unsupported.