In Matt 12:22–32 (and parr.: Mark 3:20–30; Luke 12:8–10), the confrontation between the Pharisees and Jesus reaches fever pitch and Jesus pronounces over them the judgment of the unforgivable sin, namely, blasphemy against the Holy Spirit. This logion has perplexed biblical commentators and theologians alike, as evidenced by the conflicting interpretations of the episode in the literature. Reading this text through the lens of a biblical and Trinitarian Spirit Christology provides a key interpretive paradigm by which to make full sense of this messianic disclosure episode within the Gospel narratives as a whole. The mighty works of Jesus were portals through which the presence of the Spirit might be viewed; they point to who Jesus is and demand a response in light of this revelation. This contribution from Spirit Christology helps to interpret the pericope in a way that takes full account of the response of the Pharisees in the context of messianic disclosure expectations. The blasphemy of the Holy Spirit and the unforgiveable sin logia further reveal the messianic identity of Jesus and as such form an important part of the Gospel witness to Jesus the Christ.