Some more thoughts on the unpardonable sin in Matthew 12.
First, the Holy Spirit can variously be seen as the personified love of God, the life of God, as life-giving water and breath and fire. The Spirit proceeds between the Father and Son, from the Father and Son to Christians, and from Christian to Christian. All of the gifts and fruits of the Spirit have a one-another focus to them: the Spirit is the unity-giving glue between Christians that ties the church together and strengthens our life.
So, in a sense, to blaspheme the Spirit, to quench the Spirit, is to cut yourself off from the waters of life and from the body of Christ.
Second, there is a corporate reading of this passage that complements the individual reading. Jesus is speaking here to the shepherds of Israel. Later in this chapter Jesus establishes a direct parallel between his miracle of deliverance and the nation of Israel: Jesus would set Israel free, but the demon will return, find the house empty of the Holy Spirit, and fill the house with more evil spirits. “So also will it be with this evil generation.” This is not unusual; many of Jesus’s parables are warnings spoken to Israel and her leaders as a nation, assembly, church.
Reading the passage in this light, blasphemy against the Spirit is the rejection of the Spirit by God’s people. Jesus is warning Israel that the Spirit will depart from them, a direct fulfillment of the Spirit’s leaving the temple in Ezekiel’s vision. The unpardonable sin is thus not only a warning to individuals, but also a warning to churches: if you reject the Spirit, the Spirit will depart from you.