In almost all the holy places of worship, it is believed that the cosmic energy from the cosmos is swirling around, by virtue of the place being a meeting point of energies, or by virtue of continued practice of prayer/meditation/ rituals/etc at that point in the temple or place of worship. This is the reason why we feel a sort of peace and quiet when we enter some temple, since that place is saturated with the vibrations of so many prayers/mantras/divine thoughts, which draw the cosmic energy into that place. The person who enters the holy place, becomes a conductor of that cosmic energy. It is believed that when that cosmic energy enters the person, it can cause drastic changes in the person’s physical and astral body if the person does not pass out the energy to the ground. Even though the cosmic energy is positive and beneficial, it is believed that not all human bodies are equipped to handle that kind of energy. (Some pranic healers even avoid healing babies because of this reason).
Just as a building is fitted with a lightning rod, which is connected to the ground to “earth” the electricity flowing out of lightning, the human body needs to earth the cosmic currents, which is why, many schools of thought suggest walking barefoot on dewed grass or ground early in the morning to “reconnect” with the earth energy. This is said to not only activate the earth chakra in the human body, but also to release the negative energy from our body to the ground.
And this is the main reason why in places of worship, one is required to take off their sandals or shoes. When the cosmic energy passes through the person, the person is cleansed of any diseased or negative energy by the positive cosmic energy. But I must add here that the same anology of positive energy also applies in the case of negative energy. Which is why, one should always WEAR FOOTWEAR in a place of possible negative energy, like a crematorium, graveyard, etc.