Since Paul opened the letter to the Romans with some pretty weighty spiritual and historical stuff (the Law, salvation, and a healthy dose of theology) now he brings it to street level: the gospel is also bodily, and we are the body of Christ. These things he has been teaching are not to float in space, like ideas that never touch the ground. How we treat one another really matters, and that is where salvation takes on skin. Love must be sincere, and harmony should be sought.