Q: I read that the number 11 is a number of impurity. Is this true?
A: A primary principle in Kabbalah is that all holiness that God created has an unholy parallel. The unholy 11 is the 11 crowns or forces of impurity. These can be rectified by the 11 ingredients of the incense which was offered daily in the Holy Temple in Jerusalem. In a person's personal service of G-d, these forces can be rectified by making sure to have only positive thoughts in one's mind. These positive thoughts bring about a spiritual "good smell," as did the incense. They are influenced by positive speech. (Mindless speech brings about foreign and negative thoughts.)