The baptism in the Holy Spirit is arguably the crown jewel of Pentecostal theology. The attention paid to this metaphor has biblical warrant. All four Gospels and the book of Acts describe the messianic mission as a baptizing in the Holy Spirit and fire, leading to the birth of the church. Christ experiences our baptism in fire so as to baptize us all in the Spirit. In drawing attention to Spirit baptism, most Pentecostals focused on the experiential challenge of this metaphor. Ecumenical dialogue partners note that Spirit baptism in the New Testament is also descriptive of the initiation of believers into the promised life of the Spirit, being relevant to the church catholic. Significant to the constructive proposal of this essay is the eschatological expanse and fullness of Spirit baptism as a biblical doctrine, which opens the doctrine to spiritual breakthroughs such as those emphasized by Pentecostals.