This monograph examines Hebrews' understanding of the relationship between old covenant sacrifices and Christ's new covenant sacrifice, especially as it relates to the question of efficacy. Most scholars think the author of Hebrews strips the levitical sacrifices of most, if not all, efficacy, but this work affirms a more positive depiction of the levitical sacrifices. A mystical apocalyptic tradition stands behind Hebrews' description of the heavenly cult , which establishes the framework for relating the levitical sacrifice to Christ's sacrifice. The earthly, levitical cult was efficacious when it corresponded to or synchronized with the heavenly sacrifice of Christ. Still, the author of Hebrews develops the notion of the heavenly cult in unique ways, as Christ's sacrifice both validates the earthly practice but also, due to his new covenant theology, calls for its end. Ribbens' bold proposal joins a growing number of scholars that place Hebrews in the mystical apocalyptic tradition, highlights positive statements in Hebrews related to the efficacy of levitical sacrifices that are often overlooked, and relies on the heavenly cult to reconcile the positive and negative descriptions of the levitical cult.