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As I see it, a lukewarm Christian is an oxymoron; there is no such thing. To put it plainly, churchgoers who are 'lukewarm' are not Christians. We will not see them in heaven.

Francis Chan, Preston Sprinkle (2014). “The Francis Chan Collection: Crazy Love, Forgotten God, Erasing Hell, and Multiply”, p.58, David C Cook
As I see it, a lukewarm Christian is an oxymoron; there is no such thing. To put it plainly, churchgoers who are 'lukewarm' are not Christians. We will not see them in heaven.