G.W. North discusses the nature of the Holy Spirit's manifestations, particularly focusing on the events of Pentecost and subsequent instances in the early Church. He argues that while the initial experience of speaking in tongues was significant, it should not be considered the sole evidence of the Spirit's presence, as many instances, such as in Acts 4 and Samaria, show believers speaking the word with boldness instead. North emphasizes that the lack of consistent evidence for tongues in various accounts suggests that other forms of expression, like prophecy, are equally valid indicators of the Spirit's work. He challenges the assumption that tongues must always accompany the baptism of the Spirit, advocating for a broader understanding of spiritual evidence.