'Tis the season to give to the less fortunate

Walking past the Salvation Army volunteer at the post office yesterday (I didn't say, "Sorry, I contribute only to Catholic charities."), I was thinking that it is relatively easy for people who have the equivalent of at least 200 slaves working for them (because of cheap energy) to give some extraneous wealth away. The giving of alms is not the most important sign of how "Christians love one another." At Patriactionary, someone asked whether Christians ever had a separatist mentality. I still have the suspicion that the early Christians of the Roman Empire did maintain some social distance from their pagan neighbors, or more accurately, preferred to show love towards their fellow Christians first (and also to other non-Christians of good will). They were enjoined to love others as well, but with whom did they associate and form intimate friendships? I believe that it was primarily with other Christians, and if true it should be a warning to us that our understanding of charity (which is more liberal than Christian) is wrong. I just need to find some historical documentation to back this thesis up in order to convince uhmerican Catholic liberals.