Peter Ross examines how John Calvin might assist Pentecostals in the development of a global Pentecostal theology by examining the views of each on pneumatology and the Christian’s union with Christ. He conducts a conversation between the two within the contexts of the assurance of faith; providence and guidance; and justification–each an area in which the Spirit and the union are substantially involved for both parties. He also looks closely at Spirit release, showing that this Pentecostal distinctive can sit well as an extension from Calvin’s thought. Ross shows that affinities exist between Pentecostals and Calvin in these contexts. These affinities clearly identify Calvin’s thought as a rich resource for Pentecostals; one they should not hesitate to mine as they develop their own global theology.