In Heb 9:14, the author compares the purification rites of the Levitical priesthood with the much more effective blood of Christ, “who through the eternal Spirit offered himself without blemish to God” (NRSV). The meaning of the unusual phrase dia pneumatos aioniou is much debated. Many interpreters have considered this a reference to the Holy Spirit, a position also reflected in textual variants present in numerous ancient manuscripts. Others find a reference to the divine nature of Jesus or else a figurative way to speak of his sacrificial activity. This paper argues that the reference indeed is to the Holy Spirit and that the phrase is best understood in light of the new covenant language so prominent in this section of the book.