There are some who believe Christ’s words in John 6 and Paul’s writings in Corinthians (namely Orthodox, Copts, Catholics, Armenians, Ethiopians, Assyrians, Anglicans, Lutherans) and there are those who do not believe in Christ’s words in John 6(Calvinists)
Actually, I think it is better expressed as some people THINK they are "believing" Jesus and Paul's words by holding to a strict, narrow and exclusive interpretation of them and there are others who understand ALL of the words of Jesus and Paul in context and as they were said in relation to the other truths that the Holy Bible preached. There is no place for stubborn insistence on a belief that was never really true but based on superstition and misinterpretation as well as a blind faith in a hierarchical authority that can never admit to mistakes. People are fallible, God's word never is.