What is the significance of the kingdom of God being in power, not just in word?

The truth that the kingdom of God is not in word but in power highlights that true Christianity is not merely about verbal declarations or religious rituals but is marked by the transformative power of God at work in the lives of believers. This power is the Holy Spirit's work that brings regeneration, enabling, and sanctification. Paul emphasizes this distinction to address the issue of those who are 'puffed up' with empty knowledge, reminding the church that effective faith must be manifest in real, observable change and spiritual fruit, which is produced exclusively by God's power.