2. On the Kabalistic Tree of Life, seven is the number of Netzach, the lowest sephirah on the right-hand pillar, the third from the top of that pillar. It is the number of music, passion, and pride, < href="http://www.llewellyn.com/encyclopedia/term/astrology">astrologically associated with Venus.
Some have associated this number with Lucifer (Venus, the Morning Star, is a form of Lucifer) and thus equate this with Satan. But Satan is not traditionally the same as Lucifer; this was a later attribution. Lucifer is a bringer of Light, not an evil entity.