I have been thinking about holiness in general for some time after noticing something from studying banishing rituals.
When you look at various banishing rituals, you will find that holiness repels evil spirits. This relates to how close the substance or Spirit is to the Highest Sphere. That is, in the elemental world, Fire is the highest of the Elements and Agrippa says in his Three Books of Occult Philosophy, Book I, Chapter 5, that Fire weakens evil spirits and strengthens good ones:
The Celestiall, and bright Fire drives away spirits of darkness; also this our Fire made with Wood drives away the same, in as much as it hath an Analogy with, and is the vehiculum of that Superior light; … As, therefore the spirits of darkness are stronger in the dark: so good spirits, which are Angels of Light, are augmented, not only by that light, which is Divine, of the Sun, and Celestiall, but also by the light of our common Fire.
–Agrippa, Heinrich Cornelius. Three Books of Occult Philosophy (Illustrated) (p. 29-30). Vectura. Kindle Edition.
Going a good deal higher, are the Angels, and the Celestial Gods, and above are the Gods beyond the Celestial World, all the way up to The One. Usually, simply being in contact with these beings purifies oneself.
Spirit, which underlies all things, is similar to Light, so this should not be so surprising, as Light banishes and repels Darkness.
Now, interestingly, when a person attains a good degree of holiness, simply being in contact with them often has the power to heal illnesses and banish evil spirits and uplifts the soul. And this is attested in most cultures, if not all. However, attaining that degree of purity requires a life heavily focused on matters of the spirit, a life like some of the great Sages of India have lived, and like the Saints of Europe and Sages of the Ancient Roman Empire.