In view of the two key themes found in Romans: pneumatology and deification, some pressing questions can be asked. One of these is, what is the role of the Holy Spirit in deification? This essay identifies one area of the work of the Holy Spirit presented in Romans that is often neglected in New Testament (NT) pneumatology, soteriology, and anthropology. This paper argues that, in Romans 8:1–17, the crucial role of the Spirit, as an active person in the triune Godhead, in possessing and being possessed by believers and facilitating the mutual indwelling of Christ and his co-sufferers, is best captured by a new term, namely, pneumasis or pneumafication. In other words, theosis/deification and Christosis/Christification are made possible by pneumasis/pneumafication.