Romans 8 is a powerful chapter. It states unequivocally who a Christian is. For Paul, a Christian was anyone who had the Spirit (the same spirit that raised Jesus from the grave) living inside of them. This spirit empowers them to truly live life without being destroyed. It gives peace. The spirit itself is pleasing to God. Without the Spirit we are doomed to be controlled by death bringing things. It's like working for the mob. Even when they ask you to do something that seems good, in the end you are controlled by people who will kill you.
Interestingly enough, I just looked at the title and saw the words Matter and Spirit in the same phrase. Just a random observation. That is the spirit of the matter.