A ray of holiness

‘..thus is it written (Kohelet 2:13) “Then I saw that wisdom surpasses folly as light surpasses darkness.”’: Tanya, Chapter 12

The Alter Rebbe – Schneur Zalman of Liadi – explains the analogy is used to illustrate how wisdom is superior to folly: The superiority of light over darkness is manifest in the ability of a tiny ray of light to banish a great deal of darkness. Furthermore, the light need not battle darkness to banish it; the darkness disappears as a matter of course with the appearance of light. In the same way is the wisdom of holiness superior to the folly of evil. A mere ray of holiness suffices to banish — as a matter of course — a great deal of evil folly.