Who was the he in Hebrews 10:29?

"Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?" - Hebrews 10:29

Secondly, the defector has 'counted the blood of the covenant by which he was sanctified a common thing'. This second error, says Kistemaker, is 'even more significant because it relates to the meaning and purpose of the new covenant'. In effect, those who offend in this respect reject the new covenant, for the blood of Christ provides both the essence and effectiveness of that covenant. In treating this blood as 'common' they deny the uniqueness of Christ's death and equate it to the death of animals under the old covenant. Such people 'draw back' (or timidly withdraw) from the new covenant and revert to the old. And that, avows the Writer, leads to perdition (10:29). Most commentators discuss the problem of interpretation attaching to the statement, 'he was sanctified'. Some conclude that the apostate can be said to have been 'sanctified' in the outward sense of being ritually purified by profession or baptism. We must remember that apostasy, by scriptural defintion, occurs only in those who remain unregenerate, despite their claim to be Christians (see, e.g. 1 John 2:19). Owen also argues, however, that the sanctification in question may well be that of Christ who, by analogy with the Aaronic priests, was consecrated to his saving office with his own blood (cf. Lev. 8:30). Brown concludes that the one sanctified is neither Christ nor the apostate person. Rather, he suggests, the verse should be understood impersonally as 'the blood by which there is sanctification'. - Edgar Andrews, A Glorious High Throne

I do agree with Owen and will say that it is Christ who is sanctified.