Although we can doubt that Paul was giving the doctrine of the Trinity much thought as he wrote this passage to the Romans, we can still use it to help us understand that doctrine.
Looking for them, we can read about God, about Christ, and about the Holy Spirit in these verses. We usually are focusing on the "justified by faith" part--as opposed to being justified in any other less satisfactory way. This week we focus on how that happens--that our justification by (or our faith in?) God comes through Christ. Christ models for us suffering and the product of suffering. Further, the means of that process occurs because the Holy Spirit pours God's love into our hearts.