Faith is required only when we have doubts, when we do not know for sure. When knowledge comes, faith is no more. Sometimes a person is tempted to think, I can’t become a Christian because I still have doubts. I’m still not sure. But as long as doubts exist, as long as the person is still uncertain, that is the only time faith is needed. When the doubts are gone, the person doesn’t need faith anymore. Knowledge has come.