There exists a difference between Knowledge and Fact. One can think that they know something and yet be totally fooled, for example a person may read a Bible translation and think that they know for a fact the meaning of what the author wrote. He may put his head under a Guilutene believing that he knows. He might be right but unless the author told him waht he meant he really does not know even though he is comvinced that he does.
Knowing that somemthing is true involves measuring (physical obeservation), believing that something is true involves reaching a conclusion.
In order for someone to really know that something is true or factual, such thing must be measured and the person that thinks correctly is conviced that such is not an illusion if he measured correctly. A person may say I know that have 50 cents in my purse yet be mistaken becuase he miscounted or did not see clearly yet another person can claim that he knows that something is true and have accurate knowledge.
Some people are so fooled that they believe that they know and think that they know that something is true or a fact but are in error.
"You know neither the Scriptures nor the power of God" The Saducees were mistaken in what they believed that they knew.
What counts is what is a fact. Fact is not contingent upon knowlwdge of believe. A vaccine will work wether you believe it or not or know it or not.
Belief is what God requires, and Religions if you want to be a member.
People confuse believing meaning to trust and beliefs conclusions.
God and Jesus wants us to (believe) trust them, not meaning that were are required to believe in theories that cannot be known.