Disposable things, Roman slaves, to a degree. But maybe even a tough Roman sergeant-major is going to recognise some humanity - regard the slave as merely a human being less fortunate than himself? Even the Romans only massacred slaves when they revolted. I once spent a morning discussing the text with someone who tried to convince me that you could deduce that the servant was actually the centurion's lover. Well, maybe, but the Bible doesn't specify that relationship. I like to think that the soldier was capable of doing his best for the servant, regardless of domestic arrangements.Maybe I'm just naive.
But I think their specific relationship doesn't really matter, for the purposes of the story. It's their relationship to Jesus that matters. One has a need - and the other has belief. So that's the minimum requirement for Jesus to act. It's the centurion's faith that is remarkable - even beyond Jesus healing his servant. Across race and religion - reaching out to a scruffy wandering Jewish rabbi - I guess Jesus would have appeared to the centurion like a cross between the Dalai Kama and Russell Brand - mixing obvious holiness and random words of sense with apparent nonsense, spinning morals out of lilies and miracles from spit and dirt
So the thoughts of the Centurion - "The ointments have failed, and Asclepius has been pretty quiet, and the spells haven't worked. And there's a scruffy Jewish preacher who they say can do wonders. A hermit with an attitude - a man who mixes wonder, challenge and danger. Sure, I like these people. But it's not gonna help my dignity, is it? But I wonder..."
Some faith. Some humility. Some desperation. And some love for his slave. No wonder Jesus was impressed. No wonder he was able to heal.
But.... two healings of Gentiles - the Syro-Phoenician girl and the centurion's servant. Jesus heals them both - at a distance - and, as far as we're told, doesn't enter their house. Maybe that's a step too far, at this stage? Maybe this pious Jewish man only enters a Gentile dwelling when he's going to bring total healing for everybody. For now, whoever he hangs out with, whoever he heals - he's still staying ritually clean. The big revelation about all nations coming to God is being hinted at - but it's not there yet.. It can wait.