Christian Protestants typically affirm both the essential moral perfection of heaven and the sufficiency of saving faith. Yet these two commitments generatean apparently self-destructive dilemma—one I call the dilemma of sanctification. The prima facie puzzle can be resolved in at least three ways. In this paper, I articulate the dilemma of sanctification in some detail and offer an argument against a widely-held Protestant solution I call provisionism. This constitutes indirect support for the solution I find most promising, namely, a doctrine (...) of purgatory. I close by sketching a model of purgatory consistent with Protestant soteriology. (shrink)