In the Gospel Jesus told the disciples to not prevent outsiders using his name to cast out devils. Allow me, please, to point out that in Our Lord’s time all types of insanity were thought to be caused by devils. So, that other man might have been addressing mentally retarded people, asking for a cure in the name of Jesus.
What is important is Our Lord’s answer, “Do not prevent him, for whoever is not against you is for you.”
Now, back in 1950 when I was twenty-two I had to go to the office of our strictest seminary priests. He was a man who was always precise about everything, as well as demanding that we be precise about everything. But that evening something was different about him. His hair was mussed, and he had buttoned up his sweater wrong in coming to answer the door.
For the only time I ever saw him not completely sure of himself, he asked me about this Bible passage. He said, “Thomas, what do you make of Jesus saying we should not prevent other kinds of people curing in his name?”
He looked at me for an answer, then hurriedly said, “Never mind. Go back to your study haul. I’ll see you about that other matter tomorrow.” The next day he was again as sure of himself as all the cardinals in the Curia.
The problem he was having with Our Lord’s statement is that it didn’t agree with Catholic Church policy in those years. We were saying we were the only one who were right. It was a grievous sin for us to take part in a liturgy with non-Catholics. That sin had a fancy Latin name. It was Commixio in sacris.
Having been indoctrinated into that way of thinking I had no answer for Father that night. Fourteen years after that, the Second Vatican Council published its decree on Ecumenism. (Ecumen was a Greek word for the whole world, and ecumenism means the whole world coming together in one belief.) The document said:
“The restoration of unity among all Christians is the principal concern of the Second Vatican Council.”
“Very many of the elements and endowments which together go to build up and give life to the Church itself, can exist outside the visible boundaries of the Catholic Church: the written Word of God; the life of grace: faith, hope, and charity, with the interior gifts of the Holy Spirit.”