Luther

How often the Apostle uses the Greek word ‘plerophoria’*, which means such a certainty and fullness of faith that our hearts never waver but are full of certainty at all times. As I said before, Christians must know for certain what they believe, and must witness to their belief. Therefore, if you take away certain affirmation so that Christians are no longer sure what they believe, they have ceased to be Christians, and you have taken away their faith.—The Enslaved Will

*Note that St. Luke uses this also in Luke 1:1, but the KJV version only seems to pull the nuance that Luther is highlighting here.