The faith that the nun have in my shared example is that they are used as a channel or medium to course that healing energy to the subject.  That faith is like having a signal on our cellular phone.  Without that signal your cellular phone is useless.  Same thing applies to them.  Without faith within themselves and of the subject then that energy to heal them won't get through.

When I first started learning about Reiki and energy healing I also tried to find a rational explanation for why it works. For one, our whole body is made from atoms which consist of electrons, protons and neutrons - electromagnetic energy. Just like you can use a magnet to magnetize a plain piece of iron which is in fact the alignment of iron atoms in one direction so that the piece of iron becomes polarized and receives magnetic properties. The body works similarly - Reiki realigns the flow of energy within your body and even enhances your ability to channel it to others.

Thought creates matter and changes energy levels and flow within us and around us. That's why faith in one's ability, spiritual guidance and healing is a prerequisite for being successful.

When I think of laying on of hands I think of Jesus Christ and His disciples first; also the fact that He passed on the ability to heal to his disciples who retained it even after He ascended into heaven. There were also long distance healings and He told people he healed on different occasions that their faith had healed them. Check the New Testament for applicable passages... Who would have more energy than God father, Son and Holy Spirit?! Of course He'd retain that ability on earth and would be able to heal in an instant all subjects that were open to it and pass on the knowledge.

Some people would scream blasphemy here, but I am positive that energy healing is a gift bestowed on us by our creator!

Blessings!