In applying any Bible story to ourselves, we can push details aside, seeking out the core that applies to us. In my seminary days when we were lectured in Latin, the professor would say that Bible story will apply to us mutatus mutandi , which meant, “It applies to us when we have changed what must be changed.”
So, mutatus mutandi, today how do we implement the instruction against an extra tunic and not carrying silver in our belts? Some people see it as an instruction for us to practice poverty; but since Jesus went on to tell the disciples to stay in one house, and eat what was put before them, it looks like he wanted them to throw themselves on the hospitality of the people with whom they ministered.
More broadly understood, Jesus wanted them to mix with people. He wanted them to become family with them. (Fifty-five years ago when I was ministering to impoverished victims of Korea’s war, I found eating my own kind of American food to be far pleasanter, but wiser priests told me I would remain a stranger until I ate with the people. I had to sit on the floor to eat the strange looking stuff.)
Then, what about Jesus telling disciples to knock the dust off their feet on leaving inhospitable towns? Now, it sometimes helps to read Gospel commentaries written by people who knew all the customs. The commentaries tell us that in old Jerusalem the only time people were instructed to knock the dust off their sandals was when they were entering the temple. It was a variation of God telling Moses to remove his sandals before stepping on the holy ground around the burning bush.
When Our Lord’s disciples were leaving the inhospitable town what was it they were stepping out into? Where was it that they were not to traipse the dust of inhospitality? Well, it was the whole outside world.
So, what Jesus was telling his disciples was to waste no time with inhospitable people; and mutates mutandi, he is telling us not to hang out with mean-spirited people; rather, we should shake their dust off, and break away to enjoy Gods beautiful world.