Holiness is an idea found throughout the Bible. At its simplest, it simly means ‘set apart.’ The main idea is that something is set apart for a specific purpose, usually for religious reasons. For example: a lamp stand used in the Jewish temple was made by the same people as regular lamp stands, and usually made from the same materials. Only the purpose differed…some were set aside for special use, others were not.
In this way, the New Testament says that followers of Jesus are to be set apart…that is that, though there’s nothing really special about who we are or how we were made, we work to fulfill our spiritual purpose. That purpose, of course, is to live what Jesus taught, and to emulate His character.