As I note in my essay A Critique of the Penal Substitution Interpretation of the Cross of Christ , an extremely important aspect of the resurrection is that Christ as a spirit, Christ in you, could now possess the believer in a positive way as booster, the resister of Satan par excellence and greatly aid the believer in their walk of spiritual warfare. Bazzana argues:

A means through which New Testament criticism has been able to avoid dealing with the “spirit world” as a continuum has been to restrict artificially the concept of “possession” only to the influence of evil pneumata or to an illness that must be redressed by eliminating possession itself. Ethnographic study conducted by scholars like Michael Lambek, Janice Boddy, Frederick Smith, and Brent Crosson demonstrates instead that, in almost all cases, possession has a “positive” side as well, one that benefits both mediums and their social groups in various ways. It would be strange if that were not the case also for the early Christ groups, but theological and interpretive traditions have obscured this side of the coin in a very effective way. Thus, a primary goal of the Next Quest should instead be to “rediscover” such a hidden “positive” aspect… The first element that jumps out in the [Gerasene Demoniac possession] pericope has to do with the introduction of the possessed man. Mark tells readers that literally this individual “was in an unclean spirit” (anthrōpos en pneumati akathartō)… At a very basic lexical level, Paul too uses the (otherwise puzzling) expression “being in Christ” (en Christō) exactly to indicate a foundational relation for the subjectivity of Christ believers. The foundational element here is to be possessed by Christ in a way that is obviously “positive” in Paul’s mind. Of course, the human role in such relationship is described by Paul with nuances that emphasize submission, as when he says in Galatians that he does not live anymore, but Christ lives in him (2:20).20 Or when Paul adopts systematically the language of enslavement to describe his participation in the relationship with Christ. The underlying conceptualization of the self as “porous” opens up interesting venues in terms of ethics and anthropology, especially at a time like ours in which we feel a particular urgency to think about ourselves not as disconnected individuals, but as part of an interrelated whole that goes well beyond humankind. [In terms of the Gerasene Demoniac exorcism by Jesus] [t]he man remains in the region, because he has not been really completely “liberated” from Legion (and indeed that was not the aim of the exorcism to begin with). On the contrary, the spirit will return to him, but now their relationship will be more balanced, and our unnamed man will be able to use the great power of Legion for a beneficial goal, in this case the furthering of the Jesus movement in the Decapolis.

Bibliography

Bazzana, Giovanni. Spirit World in Crossley, James; Keith, Chris. The Next Quest for the Historical Jesus (p. 655-673). Wm. B. Eerdmans Publishing Co.. Kindle Edition.